The Artificer's Magic Item Savant feature (E:RftLW, p. 58; WGtE, p. 180) states the following:
At 14th level, your skill with magic items deepens more:
- […]
- You ignore all class, race, spell, and level requirements on attuning
to or using a magic item.
The Thief Rogue's Use Magic Device feature (PHB, p. 97) states the following:
By 13th level, you have learned enough about the workings of magic that you can improvise the use of items even when they are not intended for you. You ignore all class, race, and level requirements on the use of magic items.
The description of the Holy Avenger (DMG, p. 174) states the following:
While you hold the drawn sword, it creates an aura in a 10-foot radius around you. You and all creatures friendly to you in the aura have advantage on saving throws against spells and other magical effects. If you have 17 or more levels in the paladin class, the radius of the aura increases to 30 feet.
Since these features allow an Artificer or Thief Rogue to ignore "class" requirements when using the Holy Avenger, would they gain the benefit of the 30-foot aura?
Furthermore, since they also ignore "level" requirements when using the Holy Avenger, can they benefit from the 30-foot aura at 14th and 13th level, respectively?
Related questions:
Best Answer
You can use the sword
You can definitely attune the sword. The 'Requires attunement by a Paladin' line is so definitely a class requirement for attunement that no reasonable person will interpret the thief or artificer abilities as not pertaining to that clause.
It is unclear if you can use the bigger aura
This depends on your definition of 'use' for the purpose of mechanical abilities within the game. There's no given definition or guidance for this (q.v. How does the Thief's Fast Hands feature interact with mundane and magical shields?), so you will have to figure out what is best for your group and go with that. Personally, given the paucity of items that would possess a level limitation on their usage if this were construed to not be that, I am strongly inclined to let a thief or artificer use the weapon with the larger aura. Nevertheless, the rules do not provide for or against either interpretation, provided it is consistent with your interpretation of 'use'.