The Demon King Seems to Have Infiltrated the Hero's Party

Kyle, a mercenary protagonist reincarnated into another world, is chosen to join the hero's party to defeat the resurrected Demon King. As Kyle continues his adventures amidst the antics of his eccentric party members, one day, the deity who reincarnated him reveals that the Demon King has infiltrated the party. Only Kyle, with his cheat abilities, can counter the mind-reading Demon King. To avoid alerting the Demon King that he knows, Kyle begins searching for the Demon King. To protect his comrades, he must suspect them. — Description from novelcodex.org