Looking for tips on designing a plugin

I am making a plugin about legendary items. Basically random items with powers such as shears that when they hit someone, it does the damage of a diamond sword, or a bow that doesn't broadcast the kill and doesnt make a sound.

How would i go about designing the plugin for this. I will have about 30 legendary items.

 

Do you know java or at least the basics of it?

 

Are you asking for code? Or tips on which events to use?

 

I would say i am an Intermediate programmer.

I am looking for maybe some psuedocode of an example of how i might do this so my code is modifiable and reusable.

Any suggestion are welcome. It doesn't have to be psuedocode

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Ok...so bassicly you would check when your damaged by an entity if that entity is shears then,

Code:

event.setDamage(20)

which would be instant death even with full health.

 

That would only kill them if they have no armor, I believe. If you want to instantly kill them:

Code:

player.setHealth(0);

 

Are you wanting them to be only accessible by commands or you want them to be a super rare drop from mobs? Like in Borderlands 2!