Adun

From The StarCraft 2 Wiki

Adun was Protoss hero, former Executor and Templar. He is beloved by both the Protoss of Aiur and amongst the Dark Templar. He gave his life to allow the Dark Templar to escape on an ancient Xel'Naga ship by creating a barrier from the 2 sources of Protoss energy, while he himself dissolved in the process.