Tamed Monster Summons

So I went into Rundal Boss Trial Dungeon, tamed the Siren after killing all Sahagin (which advanced to the cyclops + Red Pirate Skeleton), and interestingly, the Siren A) Summoned Sahagin B) They were hostile to me

Does anyone know if this is an intended feature/if it behaves the same with other tameable monsters with summon skills? Additionally, C) While I was in Crises Escape, the Siren was not attacked by the Sahagin, Cyclops, or Skeleton D) When I 'cancelled summon', the Sahagin disappeared with the Siren.