Better to use a high level, high HP troop like Royal Griffins or Dragons. You can either:
1) Cast 'Phantom' and 'Magic Spring' on the phantom-ed unit, so you get all your Mana back and then on Round 2 cast your 'Kamikaze' and maybe another 'Magic Spring' if there's still a few left in the stack.
2) If you have 'Time Back', then same as above but obviously you can only cast 'Kamikaze' on Round 2, because you'll need to save one cast for the 'Time Back' spell b4 the end of the round.
