Equestria's most famous sorcerer had spent his later years teaching and babysitting a pair of precocious little fillies. He begrudgingly accepted his royally assigned duties... but eventually came to love his little charges.
I like the idea of him being a grump. He'd be kinda like Gru from Despicable Me. Super grumpy at first but eventually warms up to them. Also, age is not kind. Not even to the old wizard.
1-hour for the linework. It was originally a warm-up, speedpaint requested by patchworkpoltergeist. I then found it much later and threw color on it.