In the tooltip for “bless,” it claims to apply cleanse and make the troop invulnerable. Unfortunately it interacts with curse in a way that is not consistent with clense. I did the following tests:
Bless a troop, then cast EoE: bless is removed and the troop ends up cursed as a result of the weapon’s upgrade but no other effects are applied. This is the least offensive case based on the expected outcome.
Cast EoE on a troop, then bless them (I used moon rabbit to test). Result, curse is removed, all other effects remain. Bless/invulnerable are not present.
Cast EoE on a troop, then Cleanse them (I used divinia to test). Result, ALL NEGATIVE EFFECTS are removed, including curse.
Based on the tooltip for bless, I would expect it to have the effect of (3) PLUS a persistent invulnerable effect, but in fact it is even less; neither cleanse nor invulnerable is applied.