@HugeCBCan True Polymorph be cast on self? Some say only works on others, citing loss of spellcasting ability. yes, just remember that concentration breaks it and the caster could stick into the form permanently
— Mike Mearls (@mikemearls) August 21, 2014
@HugeCB @CHoffos I think you’d lose your class & spellcasting while True Poly is active, but can maintain concentration on it. yup – for instance, some magic items require concentration or let you cast spells that need it, even if you can't cast.
— Mike Mearls (@mikemearls) August 21, 2014
How can the transformation become permanent when it has an 1 hour duration?
From the Spell description. “If you concentrate on this spell for the full duration, the transformation lasts until it is dispelled.” So, if you hold concentration for 1 hour, then it is permanent.