Rooting Doogee X5 / TWRP install
Here's what worked for me, thought I'd share this.
Out of the box was on version 18 and wanted to root , so i blindly installed King Root which did work, i then installed Supeer SU me which changed the king root to super user. After that over a week i read that TWRP 3.0.2 worked for one person so using Flashify i flashed the recovery image , after changing it to recovery.img and it worked . Such luck right, i went on to read the forums as im in love with this device , Wakefield helpful was NEEDROM.com , you need to register but there are many roms and tools for mediatek 6580soc . Out of curiosity i downloaded some rar. File roms ACS different fish tools. The best to use if you've only got oneX5 is SP flash tool. Also look for mediatek vcom drivers which auto installs the correct drivers. There are easy to follow you tube videos fur flashing using SP Flash tool. The latest version had been updated for simplicity. the process basically is ( load .bin file in its respective area,( from Flash tool) and load scatter.txt in its box ( from rar. File) the whole interface will polemist populate plug go to format hit start plug in turned off phone without battery, it'll give red then yellow bar and a check, then unplug hi to firmware screen and choose to start dload only except bootloader, start , plug wait for coloured bars and check your done. i even had gotten errors due to a faulty dload and repeated the process till i got it. I understand that not all have the patience for this, therefore i suggest using flash tool of king root messes up though that's rare.
An alternative to supersu me is to root with king root then install twrp with flashify then you can uninstall / repack king root and flash Updateroot.Script available by someone on needrom. That includes super user and busy box. Then installxposed. Etc.
* Each process in the above proven tuturial has been obtained online from other sites not just xda. I've chosen 5.1 as an idealOS for me, I can't say the route to take fur Marshmallow.
This is for -b and non b only version 18, and 19. All others take your own chances but it's resilient chip so have fun.