That's Assasin's 3rd Job : Guillotine Cross , and there's few more like Hunter's 3rd Job : Ranger, Priest's 3rd Job : Arch Bishop , Blacksmith's 3rd Job : Mechanic , Wizard's 3rd Job : Warlock , Knight's 3rd Job : Rune Knight . They are not transcendental class and they can be jobchanged at any 2nd job's LV99 which means it's a better choice though if you don't like to reborn from LV1 to LV99 In High Novice. 3rd Job gives you the same LV99 and all your stats and level gap will increase to LV150 as said from the company Gravity itself.
Episode 12 of Ragnarok Online will introduce this few stuffs too. Cool huh? It's the upgraded version of WoE (War Of Emperium) !!!
Hunter's 3rd Job : Ranger's Illustration
Blacksmith's 3rd Job : Mechanic's Illustration
For that, enjoy reading!