Thank you for clearly pointing out the facts:
Warrior X 4 uses a proprietary 21700 battery with an extra negative terminal on the traditionally positive end of the cell. No other 21700 batteries will work at all.
Great review and appreciate your honesty and transparency.
Klarus 21GT-E50 will work. It is very similar to the ORB-217C50. I wonder if the battery supplier makes a similar design for other flashlight companies. 
It get it though. Flashlights designed around proprietary cells can be super annoying. It can be difficult to charge the cell in external chargers. You can’t just grab another regular 21700 cell and use it in the flashlight. Availability of the proprietary cell is a concern.
A protection circuit could be added to a 21700 without having +/- at the positive end. The flashlight tube may need to be redesigned (e.g. inner/outer tubes) to support a standard 21700 cell while allowing magnetic charging at the tail. The X4 is already so big. A few more millimeters won’t hurt.
For someone that already has a bunch of Olight torches, this could all be a non-issue. They could swap a 21700 cell from another torch into the X4 and carry some extras in a carry case.
Thank you for good review
That quote was from the reviewer, but thanks.
Glad you guys like the review! I’m really jazzed about this light and I think it’ll stick around in my permanent collection. I don’t even have a need/use for it but I just like it. Especially with a Switchback DF on it, it’s so fun.
The imalent cell for the R30C probably works also. I think I tried it in the Odin SE and it worked, but can’t remember. I really liked the X4 also! A+ from Olight. Next to the Fenix TK20R UE and Klarus XT11GT Pro V2 its my favorite tactical/duty light
Olight nailed it with this X4 and addressed the main missing element with the charging.
I actually don’t mind the proprietary cell too much. They’re here to stay so it comes with the territory for Olight anyway. The USB C makes up for it for ease of recharging at least, and you can always keep a spare cell on hand. Olight batteries are very good quality, well protected and warrantied.
Proprietary battery is a dealbreaker for me.