Dr Regal is the son of Lord Wily, according to Mega Man battle Network 5, and grew up with Baryl, the operator of Colonel.EXE
Dr Regal's Navi is LaserMan.EXE.
he is also the designer of the SoulNet and the creator of Nebula Grey, a cybernetic monster that consists of the dark energy of human souls.
he also is able to capture and control MegaMan.EXE, ProtoMan.EXE and Colonel.EXE as darkloids with a darkchip implanted in them. however, all 3 of them are able to break loose of the dark power, notably MegaMan, who gains the Chaos Unison through this method.
it is noted that at the end of battle Network 5, his memory of the previous 10 years is erased by Dr. Wily, and he restarts his life as a SciLab employee.