[X] [BEHAVIOUR] Bodyguard
[X] [NUMBER] One
If we can make this a Fiendishly Complex spell, and we have the Coin to help us do that, then it'll be far, far more useful to the Grey College than if it ends up being Battle Magic level. There are only 20-30 Battle Mages at any time, but hundreds of Magisters. Many Magisters will be able to learn it at Magic 5, and reliably cast it at Magic 7. Meanwhile, few Magisters who reach Magic 7 then go on to learn Battle Magic, or like Regimand, only learn the (safe once you learn it) spell Smoke and Mirrors.
More importantly, this will be the second direct damage spell in the Grey College's entire non-BM spellbook. Making it incredibly valuable for every squishy Grey Magister who doesn't want to die in direct combat, and/or needs the magic firepower to fight all the dangerous, magical that need fighting.