For Mabinogi special weapon upgrade , the usual requirements are: a weapon with all 5 normal upgrades completed , a gem/jewel upgrade , 30,000 gold , and either a Red Upgrade Stone or Blue Upgrade Stone. The official notice also says the weapon becomes personalized/untradeable after the special upgrade.

What the stones do

  • Red Upgrade Stone : turns the weapon into an R-Type , boosting Critical Hit Damage.
  • Blue Upgrade Stone : turns the weapon into an S-Type , boosting Min and Max Damage.

Extra notes

  • The first special upgrade attempt is 100% success.
  • Later attempts have lower success rates , and failures can drop the upgrade level by one.
  • Community guides also describe special upgrades as requiring a weapon that is already fully upgraded and gem-upgraded before you can begin.

In practice

So the short version is: **fully normal-upgraded + gem-upgraded + 30,000 gold

  • the right special upgrade stone**.

TL;DR: You need a fully upgraded weapon, a gem upgrade, 30,000 gold, and a red or blue upgrade stone to do a special upgrade in Mabinogi.