The Azov Assault Brigade. They have been criticized for having ties to neo-nazi organizations and for using nazi imagery, such as the Wolfsangel. They are often subject to Russian propaganda. It’s the most controversial unit in the Ukrainian armed forces, though there has been a steady transformation into a normal military unit since the start of the conflict. They also lost most of their founding members during the Battle of Mariupol.

An ukrainian national guard unit.

Here we’re more specifically talking of former prisoners who recently came back from Turkey.