If you are using a (somewhat) recent World Editor version, you will likely have access to special trigger actions that add/remove/modify abilities on items as discussed in this thread. A trigger like this will work to add attribute bonus to the unit, and even change the value of the attribute bonus added dynamically:Similar to number 1, I want to upgrade items through the trigger editor, for example, a champion's shield has no hp + additional gems combined with 50% success will combine into the old shield item but that shield will have +100hp and merged multiple times.
2. When a hero receives the Trueshot Aura ability, he receives an auto-damage skill that when using one of that hero's skills has a 50% chance of dealing 5xstr explosive damage to the area around the hero dealing damage to enemies. Please help me do this.