On the Neutral Route before the fight begins, Chara destroys the MERCY button while on the Genocide Route, the MERCY button is already absent. He attacks mainly with pellets and his knife.
Chara forces the protagonist to fight him, and the protagonist cannot spare Chara. The protagonist's HP can never drop below one on any given turn; this gives them a chance to heal every time that they reach 1 HP.
To decrease Chara's AT and DF, the protagonist can eat a piece of Pellets Pie in battle or talk to Chara three times. Talking to Chara only reduces her Stats if the protagonist has 0 EXP.
During the battle, Chara uses attack patterns similar to Flowey's. She also uses light blue and orange attacks in which the protagonist can see the upcoming attack pattern by looking at Chara's eyes, which flash the attack color pattern.
After dealing the final blow to Chara, the protagonist can choose to either "FIGHT" or give him "MERCY"; the "MERCY" button has cracks in it from being shattered.
Note: All damages assume no armor and LV 1.
Chara's attacks are faster and more intense versions of Flowey's attacks. The assault ends if the protagonist reaches 1 HP and does not have 1 HP already.
- Several waves of small pellets from the top of the screen, which move in curving patterns. This attack does 8 damage per hit.
- Smaller waves of small pellets (6 damage per hit) move down the middle of the screen are interspersed with massive clouds of projectiles that cover entire sides of the screen (8 damage per hit).
- Partial circles of pellets that gradually spiral in around the Bullet Board. This attack does 8 damage per hit.
- Her hands move along the sides of the screen, leaving behind large pellets that move towards the protagonist's SOUL after all the pellets appear. They home in on the spot where the SOUL was when they began moving. This attack does 6 damage per hit, but the paws do no damage.
- Rings of large pellets from the top of the screen, gradually moving from one corner to the other. This attack does 6 damage per hit
- Asgore's eyes flash blue and orange randomly, followed by sweeping strikes in the same order of the flashes of his knife, which hit the entire Bullet Board. This uses blue and orange attacks. This attack does 6 damage per hit.