Who are ISIS-K and why would they attack a concert hall in Russia?

ISIS (ISIS-K in particular) has claimed credit for the attack on a Russian concert hall on March 22nd. Will any arm of ISIS claim credit for another terrorist attack in 2024?

For this to Resolve YES, ISIS itself must take credit for the attack, regardless of who the US/UN/world believe conducted it. The attack must have occurred after the creation of this market. Otherwise, this will Resolve NO on January 1st, 2025.