How Rare is Leo?

Well, have you seen how big the red 5* pool is? Unless you use a banner where he's a focus unit, your chances of getting him (or any one specific unit) are very slim.

Outside of focus, I think it would be something like 3% chance divided by (I think) 34 possible red 5* heroes (- whoever of them who may be part of the focus).

3/34 = about 0.09% chance of pulling Leo when pulling only red stones.

That's in theory, I couldn't tell you about how it'd work in practice.

Your struggle to get Leo is same with how I've been hoping to get a Hinoka (I've never got a single one, even on the focus banners that she appeared on a couple of occasions in).

Extremely, I remember getting a normal Leo just randomly out of nowhere, can't even remember what banner I was pulling, but I do remember it was back in like March, so there were a lot less reds to pull.

Leo and Karel are the only normal heroes I dnot have and I pulled a few thousand heroes.

Your best bet is waiting until he appears as a focus unit. Don't waste time gambling on having Leo show up on an off-focus banner. Since he's 5* only, he may appear in a future legendary banner, as everyone featured in those are 5* exclusives, so hang in there.

Just wait. I'm sure his weapon will become refinable, and he will return on a focus banner.

Patience is key. Don’t waste your time right now because you could be going at this for a very long time and not get him. There was a guy who dropped $1,000 into FEH day one and never once got Hector. Don’t be that guy.

It's pretty rare. I only got mine recently because of a pity break. And it hurts more that he's only 5*.