Namor vs Tempest.

Middle of the Atlantic.
Who wins?

^wtf is that thing on his head 😂 must be the worst drawing of Namor I have ever seen.

Does Tempest have telepathy?

He can, however control water pretty much as he wishes. Magical powers. Depends if Namor can reach him and crack his skull. On the other hand, everything Tempest does to Namor will be erased since water revieves him to perfect health. In theory, Tempest could dry Namor's body though, and make it so that water wouldn't touch him.

How fast can Tempest swim?

I think it looks better than most of Namor's pics.
The thing does look kinda ****ed up, but the art is sweet, imo.
I think it's maybe his crown?

Not sure his speed's ever been specifically stated..
But he's among the elite in magical prowess, he's the one that sent Atlantis to the past with his magic power[that caused the whole Aquaman gaining a magic hand and getting kicked out of Atlantis thing]
Plus he can control water, from it's motion to it's temperature.

Yep.

So he can control water.

Unless Namor has the Trident of Neptune, or he can reach Tempest...Tempest probably wins most of the time. Although he needs to control the water very tightly. Namor is strong enough to fight back very strong waves. He's perhaps the best and fastest swimmer on Earth.

As Tempest, Garth can fire powerful concussive beams from his eyes, control and manipulate the movement, temperature and state of all water and has vast mystical powers. Garth is limited to how much time he can spend on land, though this has lengthened from the one hour limit he used to have.

If Namor can get in close and beat down on him non-stop, he'll win. Getting in close'll be very hard though.

I'd give it to Tempest more times than not.