Unable to use skills
A major bug in Ferentus occurs at any given time, usually during combat, and affects your ability to use skills. When you encounter this bug you are unable to use any skills, allowing for only melee combat. To fix this bug one must sit for a few seconds and then stand. Sometimes the bug is fixed, but other times it is not, and you should try reloging.
Chaining Skill Combos
Many consider this as a cheat and GM's would ban for it, others saw the fun of it and tried to master it the best they could. It allowed you to combine combo skills into one big and often far more powerful combo.
Endless Skill Combos
While making use of chained skill combos more advanced it was possible to cast endless skill combos. This powerful but ban-able cheat was really hard to trigger. It is known that only a few players knew of this breach and were able to trigger. Requirements were a small delay in server-connection and a stock combo of 4 character skills. Endless combos were most easy and most seen on wizards or archers which by default own a combo of 4 offensive skills with little cool-down-time already.
Still, the endless combo cut whenever the character went low on Mana or Stamina, which was required to cast each of the skills. But this hurdle could be mastered with using adequate Potions which were implemented in a later version of Xiones.
Skill functionality not given
Certain skills do nothing in some versions of the game
Mercenary clerics were chasing party members with low health trying to heal them, while those were far away or even on different areas. This prevented other players from receiving valuable mercenary heals which sometimes made mercenary clerics useless in parties if not grouped together.