Ines & Defiler
So apparently a Crit dmg roll instead of a colossi roll for defiler specifically.
With my build, with 15 inversion stacks & the full skill power bonus from secret garden the damage is higher with a Crit dmg reactor than with a colossi reactor.
Cooldown + crit dmg 31,2% = 637k per tick and as soon he is down 872k per tick (dangerous ambush)
Cooldown + colossi 2598 = 632k per tick & 866k with dangerous ambush.
My PB was 24 seconds with the colossi reactor (on PS5), pretty sure its possible to reach 22 or 23 seconds.
