NCF – Extended list of Neutral creatures.

I think a more interesting combination would be fire shield -> laurel shield + warlock < -> dragon's breath + warlock

I believe it's better to stick to the canon: keep the shield as just an upgrade and the dragon's breath as well, although it could be without it. The alternate upgrade could get an explosion like the horned demon + fire ball, then the upgrade would be offensive like in the third game, and the alternate upgrade would be semi-defensive, but it could also defend itself in an attack surrounded by enemies.