Mu Mastery?

So, is there any way for heroes to gain access to Mu Mastery? I'm wanting to take this on my Brute but it won't let me select it.

Yuou have to go villain for a bit, but you can get it. You basically need to switch alignment to villain, then do one of the Patron arcs, and then you can switch back to hero-side once you complete the arc.

Is that something you have to do at 50 or could I do it before that? I'm 41 currently and just unlocked the ability to get the mastery set and wanted that one for my aoe build. Also how does one start this, I found info online about doing it but nothing on where to pick of the missions.

You can do it any time after level 35. You will first need to side switch to villain which will take at least 4 days (you need to do 10 tips plus a morality mission to switch to Vigilante and then repeat the process to switch to villain, you can do a maximum of 5 tips per day). Once you are a full villain go to Grandville and speak with Arbiter Rein (he's just outside the main tower) he will give you a mission and then introduce you to one of the patrons who will give you a story arc to unlock the PPPs.

Note that you can do any of the Patron arcs and it will unlock all four pools, you don't need to worry about unlocking Mu specifically so pick whichever works for you (I think Black Scorpion is probably the easiest).

You can start making the switch to villain at any time during your levelling. You just need to do your tip missions and make sure you choose the vigilante path for each on. Once youve completed 10 (can only do 5 per 24 hrs) youll get an alignment mission which will make you an official vigilante. Then you do 10 more tips and go the villain path after which you get another alignment mission to go full villain. Then you can go get the patron arc from one of Lord Recluse's henchmen and do that, after which you can get Mu mastery!

You can indeed do patron arcs at 35. You still need to talk to Arbiter Rein first, he'll introduce you to the patron of your choice.