How to use blood magic effectively in battles?

[konming]

Blood magic has some great summons, but I could not find good battlefield magic. I wonder what good players use?

Blood Broil - Does not use blood slaves and AN, but has short range (20) and can be resisted by MR. Also single target and less than stellar precision.

Agony - 1 point of damage seems quite useless. Fear+0 attack would be useful, but I never saw it been effective.

Hellfire - Now we have a decent AOE attack. Still, falling fire would be much better IMO.

Harm - I do not see the point in this spell, can anyone point out a use for it?

Blood Rain - -4 Morale could be useful against elephants I think, other than that, what use is this spell?

Blood Letting - at 400 base fatigue, a B4 caster can at most decrease that to 80 fatigue. And doing 1 point of AN+MR damage, what's the point?

I admit life for a life and infernal prison are really great later against SCs, but before that, I cannot find a decent battlefield spell, or is there some secret I do not know?