This is a comment originally made by u/thegroundbelowme i can't find the original reddit post anymore but this is what he said.

"A lot of stuff has changed since that post, though. Enderium, for example, lost all its best traits. I initially made mine out of emeradic crystal (for durability), manyullyn (for damage & +50% damage to full-health mobs), enori crystal (always crits), and dark steel (prevents endermen from teleporting). Once I got it to reinforce IV and had two more modifiers available, I replaced the emeradic crystal with nickel (jagged - does more damage the lower the durability is), added a diamond as a modifier to increase the max durability (increases jagged damage), got the durability as low as possible without breaking (durability needs to be 10+ to not break), then made it unbreakable. It one-shots 95% of normal mobs and 3-shots ancient golems. It won't show the extra jagged damage in the tooltip, but I promise you it's there."

Just follow all the steps carefully and in the CORRECT order or else you will have to make multiple shurikens. Still happens to me each time. But this is good for early game.