I never have time to use lethargy sigil. Everything dies before I have the skill ready.
Is blood oat any good?
isn't it better to have alot of damage?
I mainly use Sigil against Heralds and Bosses. Makes them easy kills.
Blood Oath takes damage you take and gives it to your demon. Only hard points work for this though from what i've heard, so the stat screen lies.
Blood Oath helps survivability a lot, and Lethargy Sigil takes the speedy Heralds than can be hard to pin down and makes them easy.
More damage is definitely good, but you should already be at a point where you can kill most monsters in 1 or 2 hits even on p8 games.
Might Aura mercenary and Fanaticism Cursed demon increase your damage quite a lot as well.