Hi MCOC MODDER here
Since they removed the DLL files from v13.1.0, you can modify the client in two ways and since 9th August 2018 Kabam has introduced a new security check for certificate sign.
1) You can mod the game like @JadedNephilim said through the libil2cpp.SO file and hex editing when you get il2cppdumper and the dump.cs File to get the offsets required to modify the offset and method in the libil2cpp.SO file in hex and change bool to true or false, or change attack,etc
The 9th August 2018 Kabam protection introduced is just making the user to force to use Google Login, which is not possible on MOD APKs, because they are signed with another test key and removes developer certificate(non-root) but for Root there is a bypass which is to use Lucky Patcher and BusyBox to install unsigned- modded APK.
I am working on a bypass for non-root as well ?
You can Modify the client in many ways through memory modifications(GameGuardian), Hex Editing via .SO files