Spiral Pierce is a skill of Lord Knight job class. It ignores both stat based DEF as well as armor based DEF. It can be a one-shot killer for low VIT characters. It is very effective skill to use in WoE (War of Emperium). It is quite spammable which makes it a premiere skill for a LK.
Most ATK is not calculated into Spiral Pierce's damage. Things such as Spear Mastery/Weapon Masteries, ATK+ cards, or base weapon ATK will not add damage. Despite all that, weapon upgrades affect this skill.
Hunting Spear is the best weapon (one-handed spear; 420 weight) for Spiral Pierce, though recent updates in kRO show that it will be tumbled over by a heavier spear.
Racial/elemental/size cards or items that multiply the final damage by a percentage.
When Spiral Pierce misses, you will do the same damage as your weapon upgrades normally add to Spiral Pierce.
Every 10 STR adds a set amount of damage to Spiral Pierce that can be multiplied by cards, The Sign, Neo Skull Ring, or similar items.