Alesan99's new icon as of late 2019.
Alesan99's old icon.
Alesan99 is a forum member that joined back in May of 2013, since then he has become an bit of an icon in the community, creating multiple mari0 mods including 2.5D Mari0, Mari0 Corrupter, T0ad and most famously Alesan's Entities, which is widely known across the Stabyourself community as the best mod on the forums.
He also worked on Mari0: SE's enemy.lua , and also created the most widely-used Custom Enemies for Mari0: SE, titled "Alesan's Enemies", including tons of useful enemies such as Dry Bones, Big Goombas, and Fire Bros.
He has even created many maps for Mari0, most if not all bundled into his own mod inside of the DLC section. Some of the most well known being SMM2 Compilation,Windows 95 World and Mario Odyssey.