If you played MU Philippines before many build has been created due to blade knight or dark knight is the most flexible character in game. He can be a hunter knight where the focus of player is to increase his agility to boost his defense success rate as well his attack speed. He also can be support type where the player focus to increase his energy to increase the percentage of his swell or greater fortitude. Also there's a type of knight where the player increase his vitality and wear full HP Reflect set, this build can deal damage without using his sword though you must use your sword too deal greater damage to your opponent. The last known build that I know that many players use in MU NON Rebirth Server is is the PK Blade Knight or Strength Blade Knight this build can deal mammoth damage to your opponent it can even kill your foe without using COMBO, yeah the special skill of your blade knight where it combines its 3 Skill to deal higher damage.
Strength Blade Knight can change his job to Blade Master after reaching level 400 and finished all quests. Usually PK Blade Knight can wear all set items for Blade Knight and all weapons available. The disadvantage of Strength BK is the low attack success rate and attack speed but there's a way to increase your attack speed, by using of ALE where your character gain attack speed also by using weapon that has excellent option and yellow option from Jewel of Harmony. When you reached level 400 you can increase your attack success rate by adding points to your Master Skill Tree. This type of knight usually use his Death Stab to kill his foe instantly very effectively when using Dual Bone Blade that has pink option and sd by pass.
PK Blade Knight Build / PK Blade Master Build
Vitality: All remaining points
Energy: Base (Even you don't put energy here Blade Knight can use skill without emptying you mana)