Suppose there is companion A and B (non-undead)
A is soul mate master (caster)
B is the mate (target) and is in decay
A cast soul mate to B:
1) When Rallying Cry cast on A:
Heal A, but Damage B
2) When Rallying Cry cast on B:
Damage B
If A and B also stand on blood surface:
3) When Blood sucker cast on A:
Heal A and also heal B (abnormal, note B is in decay!)
4) When Blood sucker cast on B:
Damage B (normal)
5) If Cryogencsis Stasis cast on A:
Heal A and also heal B (abnormal, note B is in decay!)
6) If Cryogencsis Stasis cast on B:
Damage B (normal)
It would be interesting to test if target B is an undead or an undead but decayed.
