Spinner is a disciple of Stain and is determined to see the world Stain envisioned brought to reality. This leads him to the League of Villains and Shigaraki. His quirk is Gecko and it gives him the abilities and appearance of a gecko.
Spinner's first ability is a free Enhance that gives his Weapon attacks plus one speed or plus one damage for the rest of the Combat Phase. This means that he can make all his attacks faster and faster as the turn goes on, make them all hit harder and harder, or can just make them above average. This flexibility will mean that Spinner is incredibly difficult to deal with.
His second ability is free but it can only be played once per turn. It lets him build one foundation from hand and gives his attack plus two speed. This ability lets him skip making a check for the foundation so it will be a great way to build in high difficulty foundations. It will also allow him to build while attack, which is always useful.