Poison his food

The king too wears a mask, but despite having a crown on his head, he is easily identified by his fatness... You sit right next to him. He welcomes you warmly and speaks of some trivial things while he is greatly enjoying the roasted boar served to him. Sometimes he turns away to give orders to a few of his servants behind him. You can wait for a better moment to act, or you could try to poison his boar as soon as possible.