Cool premise, decent ideas, but the ecchi feels very sudden when it happens. One panel, the elf will be lifting her shirt up or something, the next panel the horny guy goes: "put on some clothes, I'm a man." or "your getting too close" and it's forgotten about by the third panel. Seems like it'd be an okay manga if the ecchi wasn't so awkwardly written. Might get better, I dunno, I only read through the second chapter.
Also, I dunno if it's just me, but the guy seemed to pick up magic way too easily. If it was this easy to use magic, wouldn't someone have figured it out sooner, even without the elf?