I reccomend Ibis paint! I do alot of Homestuck and MLP edits on it and it works like a charm!
OMG yes that program is a miracle. Its the equivalent of gimp but on mobile. It even records your history so if u upload ur art it shows a time lapse which I think is cool. Theres so many options i'll just list the ones i use
Rotating without blurring
Easy copying and pasting
Selecting and moving parts
Setting transparency of pen for overlapping shading
Adjusting the transparency of layers
Saving art in .png