This is an edit of Liareth's Thematic Phalar Aluve mod as well as incorporating some awesome weapon levelling code from MrUnderhill38.

Installation:

Install as ususal with either BG3MM or Vortex, Safe to install mid-game however you may need to equip/unequip for the stats to change. Do not uninstall mid playthrough or risk being dragged to Avernus by the devils of stability.

I made the weapon thematically fit a Paladin of Selune.

Changes:

The weapon is now Legendary rairity.

The weapon now does radiant damage instead of thunder damage, the stats of the weapon change based on the wielders level as follows:

1-2 Lv, No enchantment, or additional damage.
3-5 Lv, +1 enchantment, and 1d4 Radiant.
6-7 Lv, +2 enchantment, and 1d6 Radiant.
8-9 Lv, +3 enchantment, and 2d6 Radiant.
10+ Lv, +3 enchantment, and 2d10 Radiant.

The weapon passively casts "Selune's Moonlight", Mimicking the same effect as the Blood of Lathender, Fiends and Undead standing within 6m of the wielder within combat have to succeed a Con saving throw or be Blinded.

The weapon grants a +1 to Persuasion and a +1 to Religion.
The weapon allows you to cast Moonbeam at Level 3 once per long rest.
It also keeps the unique Phalar Aluve: Melody action.

Notes:

The weapon shimmers with white light unlike the Blood of Lathander because I find it more appealing but if people want the sword to glow let me know and i'll release an alternate version.

I kept the Finesse tag even though it doesn't work properly incase Larian did it on purpose and plan to fix it, howver if people are bothered let me know i'll upload a version without the tag.