Hassan the Younger

Ḥasan ʿAlā Dhikrihi's Salām (died 1166), also known as Hassan II or Hassan the Younger, was the leader of the Levantine Brotherhood of Assassins in Alamut from 1162 until 1166.

In 1162, Hassan sent Al Mualim from Alamut to establish the fortress of Masyaf in Syria. Al Mualim's departure was speculated by some to have been either due to a disagreement with Hassan over the Assassin belief system, with Al Mualim leaving to establish his own Assassin Order, an attempt to grow the Assassins' influence in the Levant or due to Al Mualim having a secret desire for power and kingship.

Reference

 * Assassin's Creed: Official Game Guide