Tarstones are powerful items that can be equipped and come in different kinds:
Support Tarstones
Grant a variety of improvements to all Characters
Combat Tarstones
Grant a variety of enhancements to Weapons and Sidearms
Infusion Tarstones
Allow to infuse Weapons and Sidearms with Elementals
Ability Tarstones
Allow to perform devastating special attacks with Weapons and Sidearms