Shapechange allows you retain your Intelligence & class features, while taking up your new forms’ physical stats. In theory, this means that a Bladesinger could change into a Marilith and get 7 attacks with crazy modifiers using Bladesong, while having really high AC and Concentration saves.
However, a few questions came up:
- Swords Not Included™: You would need to supply 6
melee weaponsrapiers to benefitget the most out of Song of Victory. How could you effectively carry these before Shapechanging, and effectively wield them afterwards?
- Assuming this goes smoothly, would your weapon attacks be at +11 to hit (+5 Dex due to finesse + 6 proficiency), or the Marilith’s +9 (which appears to be +4 from Str, due to longswords not having finesse, and +5 prof)?
- Would the damage be 6d8 + 60 for the sword attacks (w/ Song of Victory), plus 2d4 + 9 for the tail?
- Would AC be 18 + 5 (Bladesong) = 23 (+5 optionally with Shield) ; and +15 Concentration Saves?
Granted, it’s no Wish, but vs a handful of powerful targets (especially with Spellcasting), I feel like it could really bring enemies down quickly and hold the line, ideally if Hasted by a party member.