Dang, I spent 30 minutes rereading from the beginning, as I barely remembered anything.
MC reincarnated into a game he played, as a strong npc knight captain that will die early in the game. He's going around trying to make sure he survives his death event.
2 protagonists are new soldiers in his company, Kyle and Mia. Mia is Kyle's childhood friend. 3rd protagonist is a civilian saved during an event in first chapter, Reiah. Kyle and Reiah are reincarnated heroes from thousands of years ago, who sealed a demon god. Worshipers are trying to revive the evil god, game's goal is for the heroes to remember their past and powers and defeat the god again. These 3 characters are the ones in the 2nd half of this chapter.
MC hands his captain position to Mia, gives Kyle a good weapon, and quits to carry out his plan. Got 3 sidekicks and beat the boss of a DLC.
Sidekicks. First accidentally saves a random merchant NPC girl, becomes his errand girl. Wins money from card counting at a casino. Wins in combat arena, has merchant girl bet all his money on himself. Triggers an event for a syndicate assassin to appear. Uses trigger phrase to take control of assassin girl, she sees the handler as onii chan. Goes to syndicate base to save a 2nd assassin girl and convince her to join him. She can't be mind controlled but can detect lies. Hides the truth and tells merchant girl these 2 are his little sisters
DLC Boss. MC has merchant girl use his money to buy stun items. MC and 2 assassin girls go kill the syndicate leader, boss of a DLC. Uses hundreds of stun items on boss as an exploit, 2 girls handle the mobs. Fight finished in this chapter.
Not sure why protagonist trio shows up at 2nd half of this chapter and how mc is coincidentally nearby.
That's my summary, hope it was useful, and not full of mistakes.