Complex sentence: Caracharoth is a great wolf mostly called the "Wolf of Angband" or "Red Maw" he was involved in the Quest For The Simarils when Beren, Luthien and Huan encountered him when they were escaping Angband.
Split into simpler sentences: Caracharoth is a great wolf mostly called the "Wolf of Angband" or "Red Maw". He was involved in the Quest for the Simarils when Beren, Lúthien and Huan encountered him when they were escaping Angband.