He sells things that are somewhat good for when you're questing in Balmora.
He stands near the bridges joining the two sides of Balmora. He wears iron armor, so you can see him quite easily. Challenge him, if you'd like, he's not too easy at first!
Install to Morrowind/Data Files folder, then enter Data Files menu when launching Morrowind (must be on the launcher), and tick MAKI.ESP on the list.
This is really just me and my brother experimenting with The Elder Scrolls Toolset, which is extremely easy to get into. You can expect more of these in the future if you're interested!