Ascend is a perk introduced in House of Wolves. Ascend permanently upgrades Legendary and Exotic Weapons to the highest Attack (365). It also upgrades Legendary and Exotic Armor to the highest light (??) and defense (??). Ascend does not reset any of the perks or experience you have already unlocked.
Cost:
Legendary Weapons: 1 Etheric Light, 20 Spinmetal/Helium Filaments/Spirit Bloom/Relic Iron and 750 Glimmer
Legendary Armor: 1 Etheric Light, 20 Spinmetal/Helium Filaments/Spirit Bloom/Relic Iron and 750 Glimmer
Exotic Weapons: 1 Exotic Shard, 25 Weapon Parts, 1500 Glimmer
Exotic Armor: 1 Exotic Shard, 25 Plasteel Plating/Sapphire Wire/Hadronic Essence, 1500 Glimmer