I did it with
Trickster’s Shot - Titan +9 with enchanted and hunter’s mark.
Sorrowful Banner - edit, actually I used this banner in TOD with a different troop 1, must have used Guardian Banner.
I managed to get to about L 420 using various hero classes, but barrier on brown helps a lot, so when Titan it became easier.
You can win with 3 troops as well as 4 ok in this team, if you lose TGM.
Ideally you entangle Silent Sentinel with a 4 gem match but if TGM takes a skull hit, at 500 it most likely kills it. I think from memory Sentinel skull attack is 260, and my TGM had about 200 armour and life, so 1 skull it’s dead.
Forest Troll starts with 1/2 mana as does hero.
Fill TGM or F Troll. Spam FT - no green in AI team (this is very helpful for the first boss room and the final boss room). Matching browns helps hero as 1 brown match saves hero from Gargoyle first cast.
Devour Gargoyle with TGM. TGM afterwards has around 1200 combined armour and life, (more if sentry buffs GG) so can withstand about 5 skull hits from an unbuffed sentinel. Then just spam FT and Trickster’s Shot. Leave SS up, let it grow from ethereal sentry casts. Fire FT anytime, regardless of numbers of greens, you will take them usually and if it matches any it fills Trickster. Usually this is how you get 4 gem matches to keep entangle up.
TS hunter’s marks the first enemy, so TGM can skull hit for 300+ if you get a skull, so slowly SS gets in range.
So after devour, build to fire TS on Eth Sentry, then Arcane Golem - 380 damage approx after hitting them both - leave SS up. Eventually you will either have to cast TS and get the minimal gain of 2 magic as no armour left on anyone, or SS you haven’t skulled enough, so you will get some +magic when striking it.
Yes 1 sky skull defeats it, and in my game vs it, my first entangle wore off after 1 turn, but fortunately I got TGM full and another entangle up.
Getting to the boss room, check the middle room, if it is Kruarg, in slot 1, this does not work unless you are extremely fortunate. I think I had Kru around L430. He is immune to this strategy, so I am not quite sure what troop I swapped, but I had been using Mantis Shrimp in a similar team for Manticore and Kru rooms where they appear in slot 1 in TOD, but he was colour blocked out in the delve iirc. Leviathan and Chief block FT too, I’m not sure what I did in the delve to get past it, possibly avoided skulls and got Maw up and killed it first with skulls and TS.
Other rooms, the hardest room was Orc Warband as the veteran likes green, you have no red and Drake Rider and Fel Dras, loop red, but again, once you devour someone it becomes easier and TS will kill them one by one after it’s taken 3 full armours.
You need luck as well, I got a 5 match of yellow on turn 1 in 500 room.
I have a video of doing 500, but it’s kind of large