Sword of Life Stealing Macro?

Hello! I'm very new to Macros and a little overwhelmed but I was wondering if I could make a macro that could automatically activate upon a critical hit with my sword that would roll 3d6 and display it (as damage for the DM) but then add that same total to my temp hit points on my character sheet? Thanks! Ames

The only way to make any changes to a token or character sheet requires the use of an API script, which requires the game creator to have a Roll20 Pro subscription. Depending on which game and character sheet you are using, it might be possible to put the 3d6 damage into a weapon's critical damage field, which would solve the first half of your question.  But without a Pro subscription and an API, it won't automatically be added to your temp HP.

Thanks! This was really helpful!