D987654321's GW options

You can't use Lushen against Theomars, not without cd resetting or buffblocking him. You're asking to die. If you're zerging arena and Lushen would kill (or maim, if he's hitting with someone else) the enemy team and all that's left standing at the end is an endure'd Theomars, cool. If he's on violent, I'd love to see him violent so much he can kill 4 people (realistically impossible if the mons aren't all oneshottable, some would take 3 rounds), and the survivors need to do 1 damage. And obviously if he's some idiot on vamp, which I've seen, that's moot, he can't proc turns. But this isn't arena, you don't want to throw someone away, and it's very awkward going after Theo. Even if you bring a Chloe, Theo is built on both Fatal/Rage and Violent, slow and fast for either. Mine is atk/cd/atk and still has 168 speed before lead/towers, and violent. Realistically Theo can oneshot Lushen with an atk buff (Rage ones don't even need that much), defbreak being overkill. Yes, Lushen can "kill" him back, but you die on his endure turn, best case scenario losing the Lushen but winning the fight.

Worse case scenario, your Lushen's faster than Theomars. Goodbye, you don't even get to hurt him if he's got his own Chloe. You spend your turn crying, then he takes his and kills your DPS. You can dick around with this in arena, I'll occasionally bring Chloe+Verde since she's fast enough to take turn 1, check speeds, fanatic if necessary, or pass the turn, get ATB'd from Verde, and then do it. If something's slow enough, she can do this without Verde's help, but that's basically a base speed Theo for me. You don't have as much room to play with only 3 mons while covering sufficient bases.

Without a decent PVP toolbox, going after Theo is a catastrophe waiting to happen. The most consistent thing is making him 1-turn-gankable, either buffblocking (Megan being the easiest way to do this), or turning his passive off (Tesarion). The separate issue is doing this before he gets to move. He can oneround anyone if he procs, and you can't tank him unless you intentionally let someone get defbroken. He isn't like Zeratu, where oblivion makes him significantly less of a kill threat, he'll just die if you hit him. Just bringing a rezzer isn't enough either, he's usually faster than other DPS. He'll always take a turn before a rezzed Lushen, and just kill them again.

One of the absolute best ways to kill him is Eshir. Massacre's dispel pulses realistically are the death of him. People with Eshir atm have it pretty damn good with all the Theos running around. Still doesn't help Theo being untankable if you're slow, and being able to tank mons is what makes a lot of fights consistently winnable. Also why I've made luxury PVP 6s or rune setups for the purpose of just tanking, being a giant wall. Had some nitwit in chat bitching at me for saying Rina had a purpose, as if I was suggesting to put her on AD to be a useless lump. Especially with a resurgence of wind DPS (especially violent bruisers) attempting to counter people abusing Theomars, she can be essentially unkillable for an AI that can't swap targets or properly focus fire. I have my Kernodon for this because I needed skillups for Chloe and Michelle, but tanks are just... so important. I'm still shivering at the Zeratu this week that hit me 5 or 6 rounds worth of swings (not including him turngranting himself from buffing), if my Groggo wasn't built to be a giant slab of concrete, I'd have been fucked with basically any other comp, including with Chloe, because he did it on turn 2 or 3 after getting rezzed. I mean, if I had a no-rez ganker, yeah, but I don't.

He does not have the runes necessary for Chloe to work. If she isn't blazingly fast, she can't do her job when she needs to. Just spd on 2 isn't enough, you need substantial subs.

Vero/Chloe/Lushen is a complete gamble in your initial example. I would put money on the enemy team, despite the AI control. Both (why on earth are there two... all those essences...) Veromos' are slow, the swift one is slowish by violent standards. I'm not happy with mine's speed and it's 181 or something like that. Also, the violent one is the one with the skillups, so that swift one's useless regardless. You can safely assume Chloe - when properly built - goes first here, if Vero or Theo outspeeds, you are TREMENDOUSLY outclassed rune-wise and the rest is kinda moot. So far so good. Whether or not your Vero outspeeds theirs doesn't matter, either you go first and stomp, or you're immune to the stun. Of course, if you were slow, Lumi will always hit Chloe, so you're letting your healer/fanatic-er soak the CD resets, but no way in hell Lumi's that fast. It's just an issue for later in the fight, like if you somehow kill Theo and lose Lushen because you don't have a way to tank Veromos. I'll mention that later.

So, your stomp will go off, so you at least have a chance of stunning. Saying hopefully you CC Lumi is wishing for the least likely thing. She's one of the only mons where people regularly build with resist in mind because of so many Lumi-soloing-Dragons guides. A lot of mons actually do take resist, particularly tanks (whether it's healers that end up tanking, like Chasun, or someone meant to soak but needs to take turns, like Ramagos). You just see it more often the better their runes get. Lumi is the least likely to be stunned of the 3, though, especially by Lushen, who will always have low acc without screwy stats. Theo is most likely to be hit, which is good, as he's the one that ruins everything. Opening with surprise box is going to get you killed, though. You're already fighting Theo when assuming multiple turns. What happened to the gap of time between the fight starting, Lushen using the box, and then Lushen using Amp magic on another turn and then GENEROUSLY proccing endure?

Bear in mind if Vero is lead, Theo is guaranteed to have more than 15-16k hp, even ignoring HP subs will leave him with like 14kish or something paper doll, then add Vero's lead and tower buffs. My Lushen is +1377atk, 188cdmg, and I'm crit-capped vs water, my cards are about ~5k including my tower crit dmg (maxed) and atk/windatk (not maxed, lvl 5 or something). 8k if you bring an atk buff, but you aren't. Amp isn't lethal to him here from me, only about 15k. Close, but no banana. Bear in mind his Lushen is +926atk and 142cdmg and I'm assuming worse tower buffs, and only 48% crit (85 necessary to cap vs water). So if mine isn't quite lethal, his is far off. This is all relevant, but the bigger issue is simply... Theo would target and kill Lushen in between the box and amp regardless, unless he gets stunned, and if that doesn't happen, then you get to the endure turn which you acknowledge is win/lose territory. Unless, again, Theo gets stunned. You said Theo takes out Chloe. Theomars, in my experience, beelines for low hp targets, even though realistically I'm aware he does pingpong and occasionally hits tankier mons. Coinflip at best, but you can't assume he'll pick Chloe, Theo picks who Theo picks.

What I wanted to bring up earlier is this. Since Lumi sucks at sustain damage healing, say Lushen dies but you finish off Theo anyway because it's so long between her heals. Or say you kill Theo but the untanked Vero decides to violent and procs twice and Lushen, who was magically full health, dies anyway. Your Vero/Chloe against Vero/Lumi, now what. Hard to dot damage without violent streaks, which the AI will get more of. Secondly, Lumi will be hitting Chloe. That means she'll be resetting Chloe, which means you could keep getting cut off from healing when you want, or possibly never get to re-fanatic. So even if you trade DPS mons (which is in the AI's favor anyway, since you hurt your options for other battles), you could get behind and not be able to fix it. This'll take a bit of time regardless, so even if Lushen's alive, some bad luck will get the Vero going after you.

What it all boils down to is, Theo isn't worth it without more concrete answers. Alternate example - Ganker DPS (someone that can oneshot a squish, preferably ST DPS where it's focused in making 1 thing really dead instead of a lot kinda dead) + Chloe + Tesarion, with Tesarion barely faster than the ganker. Chloe fanatics. Tesarion oblivions Theomars. Immediately afterwards, you burst and kill. He doesn't endure, and then he's like any low-hp DPS on a defense (dead). [Note, because of resists, there is NOTHING foolproof about Theomars, there are a tiny handful of unresistable effects in the game, so if your plan involves oblivion, or buffblocking, or siezing it off in a 1-2-3, or spamming stunlocks, or defbreaking into Eshir's burst and hoping one of the hits dispels endure... it all CAN fail, and he'll be able to take a turn]

For the other team:

Triple light team with a ton of debuffs between bella's break and Aria's shitstorm and you chose not to bring cleanse/immunity or tank the element. That's exactly when you WANT to bring Veromos. Pure element team, that's a godsend, those are the safest teams you could go against in GWs. Space is at a premium with only 3 slots, and you take care of tanking 100% with 1 slot, don't even have a rogue healer that could target a squish, and only 1 AE (Aria's 3rd). Aria doesn't hit that hard, Bella hits for nothing, Ahman is okay damage with a defbreak up, but he'd need a bunch of procs, and he's typically quite slow in order to hit violent+critcap+decent hp. You're turbulencing the only person who ISN'T making you lose compared to Aria's AEs or Bella defbreaking. Yes, he's potentially more damage than Aria, but that damage is only a threat because Aria and Bella exist there. Aria is going to be the squishiest, and both her AEs and bella's defbreaks are problems, and each is an extra debuff blocking the other from Vero cleanses.

For reference, since I felt like mine was too squishy before, I went hp/hp/def on my Bella, he has just under 26k hp and 1370defense, paper doll, with 191spd and still managed to keep 63% accuracy. That's before Ahman's lead, or towers. Even if Aria's built for cc/survival, which is likely, she has worse base hp and base defense, and likely at most 2 defensive runes, possibly only 1. A pretty standard ToA build is spd/hp/acc, because if you use 2 defensive runes, you're making acc and spd compete for subs instead of being able to freely grab spd. Aria's a ToA goddess, and likely runed as such. Even though she's almost never going to be yolo, she's almost guaranteed to be weakest, but she's very likely to be fast.

I'd want to drop her first just so she's down. I didn't notice what you said about her being 35, I'm pretending all 40s, and pretending they're using equivalent runes to me. I also wouldn't bring Baretta at all. Yes, the other team is likely fast (at least Aria/Bella). However, if you're using Vero, that's 1 slot. You REALLY want cleanse/immunity here, that team has a clusterfuck of bad debuffs. You need a healer if you aren't zerging, and you need a lot of synergy and your speeds sync'd to do that well in arena, let alone GW with only 3 mons. I could zerg this with a few comps, but I don't suggest doing that at your rune/mon levels. That leaves one slot. Baretta is not going to kill here, it's basically up to Vero. It's a team with a burst AE heal and sustain AE heal, albeit with no way to cleanse. The dots get heavily mitigated by the sustain, though, and like I said, Ahman is the smallest threat (he keeps them running, but without a fury of violents with a defbreak out, he's just... not gonna do much but keep healing or provoking Vero). If the healer was Bella, not Chasun - since defbreak does more than atk buff for Vero's damage - Vero *COULD* be enough, especially with good timing on Baretta's dots, but it has to be all at once because, again, two enemy healers. You're relying on violents too, they can heal through his sustain. That means you're relying on too much chance for my liking.

Vero/Bella/Lushen or Vero/Bella/Hwa is a much safer comp for this, based on his mons, and I'd take Hwa. Vero/Bella is a fast pair, and Hwa goes well (especially if speeds go together nicely; when I was relying on those 3 together often, I shifted runes so it went Bella->Vero->Hwa so I could fully use the defbreaks on openers. It's a tossup in terms of Bella/Chasun when pairing Lushen, Bella's better for burning 1 target, Chasun's better for an opener amping unless she's slower for some reason than Lushen is.

Separate note, but even with the spd lead, at current spds, I would realistically assume his Baretta would be outsped by both Bella and Aria.

Also, in your example, while you might've been using his mons' current speeds in your example, you want defbreakers going BEFORE your dps, not after. A Baretta opener, who cares, but Hwa going before Bella misses out on turn 1 kill opportunity. She's still my go-to when I need to bring a fire DPS, which is happening more and more with all these people in C2/C3 that somehow all have the wind MK and Ritesh throwing them on ADs to try to curb Theomars.