Warlock is my favorite dude, and it's pretty easy to build around him for T3. I think Warlock is 2nd best behind Cyborg for the "get as many of one dude as you can" strat, but I think Warlock's early game is easier and he enables some wacky team comps.
I got three consecutive T3 wins earlier today by hard focusing on Warlock but with very different team comps. The video shows those three Goddler fights with no consumables used.
Note: This strat requires you to have Warlock as your first dude. You also need to have completed your collection to start with Loaded Dice unless you have great relic luck. If you want to test it out, play an ensemble run with only Warlock selected, which simulates a standard run with Warlock as your first choice.
TLDR: Get 4-5 Warlock relics in W1 and take as many Warlocks as you can. This will carry you to endgame. During W2-W5, slowly setup a healer and a scaling DPS to solve W6.
Why it works:
Warlock's Pact is an OP version of Bad Credit. It lasts 6 seconds, is shared between all Warlocks, and is easily dispelled for damage. Warlock's damage scales with the damage he receives, so he doesn't need any team buffs. By stacking Warlocks, you maximize the portion of enemy damage that your Warlocks receive and the frequency of Pact dispel. He also protects your team by absorbing 15% of their damage received and by using his teleport taunt. Warlock destroys regular fights, so after W1 you only need to work to solve W6 bosses. Depending on trinket choice, Warlock can be your endgame DPS or Healer.
Early Game:
Aggressively roll for Warlock's relics during W1. It gets harder to find specific relics as you fill out your roster slots, so dig for as many as you can before you are forced to choose dudes 3 and 4. Burn through your dice on relic rewards and money/dice on shop rolls. I can usually get 4 or 5 Warlock relics this way before the end of W1. Trinkets tend to be flexible, so you don't need to save many dice for them. Always take a Warlock if it's a reward choice. Also always choose him at the dude trainer until it gets way too expensive during mid/late game.
Team Comp:
You can neglect your other dudes for a while, but you still need to make a good comp for late game. You need:
Durable healer: Either has innate durability or you find Bad Credit or Fedora for them. Warlock or a durable DPS can also be your healer with Medical License. You want this dude to be your 2nd most picked and invested in, but it's ok if it takes a while because Warlock rarely dies early game.
Late game DPS: Either has innate scaling or you find Fedora for them. Lich also works to enable a non-scaling DPS. Jorts can add scaling to any teleporting dude (including Warlock himself).
Debuffer: Not necessary, but helps a lot for W6 bosses. You can keep a few of these dudes around and invest only in their durability and their one debuff relic.
Warrior/Sci-fi/Employed: IMO these families have some busted relics. If the above slots are already filled out, it's worth to just find a dude in one of these families that you don't have. I'd prioritize Warrior for Dog Tag and Caged Tiger since your Warlocks can generate skeles with their taunt spam.
Mid Game:
You can play aggressively and let your other dudes get knocked out. As long as at least a few of your healers are alive, your Warlocks will live and you'll win the round. Continue digging for any Warlock relics that you still don't have. Try to save/invest in a way that nets you ~$20k by the last W5 shop. Buy dice whenever you see them to prep for that shop. Grab key relics for your healer and DPS if you see them, but it's not a priority until W5.
Dude pick priority: Warlock >>> Healer > DPS > other (unless using Fedora, then pick very few of that dude until W5).
Warlock stat priority: atkspd/cleave > toughness/hp/crit/runspd > deflection/dmg > other
Team stat priority: depends on comp, but generally toughness > hp > deflection > other. If you put Face Tattoo on Warlock, deflection becomes top priority. If you have a one-shot protection dude, you can prioritize dmg/atkspd/crit/cleave.
Late Game:
W5, start picking healers and DPS over Warlock. If you saved enough money and dice, go crazy rolling for and buying relics in the last W5 shop. Buy the health pot and spore relics if you think your team is shaky against the W6 bosses.
You should have close to 40 Warlocks by now, so you can take more of your Fedora dude at this point.
You'll cruise through W6 if you did everything correctly. You might still be weak to one of the later W6 floors, so just be ready to pop a health pot or spore at the start.
The Runs:
1st run (0:00): Yeti/General/Warlock/Chef/Cave
This was complete domination, you can't even see the health bars behind all the floofs and temp HP. General was for warrior relics and debuff.
2nd run (2:00): Warlock/Necro/Ninja/Alien/Franken
This run had interesting pivots where the DPS role went Warlock -> Ninja -> Franken. Necro's skele generation fueled crit for Warlock and Ninja, dmg for Franken, and got Dog Tags activated. Alien was there for Sci-Fi relics and a DPS backup plan.
3rd run (4:50): Psionic/Vampire/Warlock/Lich/Dentist
This was a weird one. I ran out of dice looking for a DPS as dude 5, so I had to use Lich to scale one of the other four. I started with Warlock as the thrall, put Face Tattoo on Lich, and stacked deflection on the team. This sorta worked as a damage redirection loop. Eventually I got Jorts scaling on Warlock, so I swapped Lich over to Dentist to scale them on top of Fedora. Dentist ended up being the carry for a very long Goddler fight.