Honestly, I have no clue why devs haven't developed proper keyboard and mouse support, lucky for you, if you're using Linux, you can download a small program I've made allowing you to play the game with mouse and WASD: https://github.com/duzda/TitanSoulsLinuxEmulator

Sadly, the control keys are not bindable but I tried to choose keys that make sense and most gamers are used to, in the worst case, it should be very easy to edit in the source code. The mouse support is by no means perfect but it's as good as it could get! Still, way better than arrow keys.

For usage please see the github link or simply ask in the comments! :)