question about new hero thanatos

this not effected by debuffs what does this exact mean is mk barring from death a debuff? is charming fox round skill considered a debuff? need too know these things for future reference when it comes too starcaller and him doing supremacy how does that work? will starcallers random still might go on the 2 highest attack heros or other then that since thanatos does exact 2 strongest is there an order too which of their battle skills will go first/apply?

https://prnt.sc/BbAopSyase-E