Luin, not RuinFORUM
For some reason, they keep naming Luin as Ruin. This is a mistranslation, most likely by a translator who didn't know the reason for the name. Japanese has no L, so R is often used as a similar consonant. The translator probably just assumed that this was the case here. Luin is her proper name though. Rufus has two child named after mythic weapons. Durandal was the named sword of the legendary paladin, Roland. Roland served as a knight under Charlemagne and his sword was on the same level as others such as Masamune or Excalibur. Luin was a spear of heroes in ancient Ireland, and the spear was later merged with the weapon wielded by Lugh, a prominent god of the Tuatha de Danann (associated with oaths and laws). If you look at Luins S rank costume, she is actually named as the Spear of Vengeance. In addition, her skills are cursed spear and phantom lance.