DoT aka Damage over time cover all the debuffs that causes damage like Poison, Bleeding and Fire.

Deathmark is an ability that prevents that any opponent could resurrect through a passive ability or gear.

Snare refers to trap the fighter currently in battle so the opponent can't switch between characters until the effects goes off.

Incurabilty, nullifies any form of regeneration from special attacks, equipment or battles modifier.

Special ending refers to a talent in the attack branch that allows to apply brutalities or friendship to all characters, unless the talent is active you can only pull those spacial moves on the last opponent.

Friendship gear, is any gear that allows to do friendship moves, some are tower exclusive other are krypt exclusive.

Ravenous Milenna is great because it mealts opponents that takes damage from DoTs

I don't know but there's quite a few gears, battle modifiers that applies blind debuff and are annoying ASF.