The reason why the onion knight didn't appear when "Dark Soul 3" hit the giant king is that if you kill Al delic before hitting the giant king, the onion won't appear. The solution steps are as follows:

1, hit the fire on the tower with giant archery. After that, Yilu Hill in Lenglie Valley will first go to the hole where there are many chastity sons in the river, and don't go to the underground prison. If you go in through that hole, you will meet Brother Onion. Then, if you have been pitted by the bald head, you will find the onion knight in the well in front of the clean body chapel. You will go to the bald head to help Brother Onion get his armor back. After this story is finished, you will be imprisoned in the underground.

2. Then, in the capital of sin, don't go down from the ladder next to the bonfire in the direction of the boss, go down to the inside of the building, and then go down from the side with a gap. Explore first. A magician's roof kills the magician first, and you will find a window without railings opposite the magician's roof. Jump over and go forward, and you will find Brother Onion. Open the door with the key, and you will find the Onion Knight. After talking, you will be given a wedge-shaped stone disc.

3. At this time, go to fight the giant Yumu, and the onion knight will be with you. The onion knight is fragile and easy to be killed by Yumu. In fact, it doesn't matter if the onion knight is killed by Yumu at this time.