Zamul

Zamul was born as his brother's substitude to be King. Every Isaref Queen must only give birth to one heir at a time so that made he a special child, having gained immortality since the moment he was born. So, to protect Asrut the true King of Isaref from being targeted by the enemy, Prince Zamul was made to replace his brother's status, living under the name Asrut. He cannot die of illnesses or any fatal impacts, however Zamul can still feel its pain whenever he was hurt or poisoned. He has been endured them instead of his brother, having been seperated from him since little with Bashim being his only support and parent. (Source: 1001 Knights Wikia)