Am I misunderstanding what the spell does? Does it only let me steal higher level rankings? Why would it let me kill my champion then? If that's the case, can we clarify the text and prevent useless champion death?
Yes, the description could use some clarification.
The spell allows you to gain access to a spell type you do not already have. In your case, that would be Air, Earth and Fire (and possibly Life, if a Sovereign with a rank in Life magic surrenders to you). You cannot use it to increase your spell ranks, however. Also, no matter what spell rank your sacrificed champion had, you will only gain one rank. For example, you could use Steal Spirit on a champion with Fire III to gain Fire I, but you cannot use it to gain Death III by casting it on a champion with Death III (or higher).
