Heh I remember bringing up that trick during the non-character tourney. Used undine on blade wyvern then having it switch with high agi undead to massive return undeads using levi.
Anyways, another one of those cool perm/temp stat skills is belphagor's beyond help. It is interesting that it makes the current attack permanent, not just give +50 perm attack as one start. (It is also interesting to know that he is a start skill, different from the rest' auto skills. That means that he is weak to emana but can be combo'd with pixy greatsword) Anyways, so a good combo with belphagor (and perhaps other units on the field) would be heierrat field commander ss. That ss focuses belphagor and gives it 20 attack/2 agi boost. So when belphagor makes the attack permanent, it will be 50 rather than 70. Next turn, if eskatia or whatever is still on the field, he'll have 120 attack. Very nice way to boost up attack quickly and make sure you get those one shot kos.