Extreme circumstances often have extreme results. Artemi was incredibly sheltered , full of self-doubts because being the creator was the only thing she really had going for her. Suddenly meeting two people who don't shower her with praise just for being the creator's chosen, and them appreciating Artemi for who she is would change her quite quickly. They found her lightning magic pretty awesome, whereas before, her lightning magic was a source of doubt for her (since the other chosen ones weren't tempest mages).