So I had noticed a thing for a long time but didn't know if it was intentional or not but after the super charge fix I thought I would report this. When you use Maelstrom on an NPC or an actual player it does not increase your rage or your opponent if it's a real player . I have tried everything tested it against highest defense but still the rage on both attacker and defender doesn't increase.
The "ultimate" skills don't increase your rage. (massacre, surgical strike, maelstrom, etc...) The old blood mage supercharge had a "rage bonus", but that was an exception.
Massacre does indeed increase my rage (as I just tested it), the rage *bonus* was increased rage on top of normal rage, there is a normal rage gain from using these skills.
The ultimate skill does not increase either player's rage, which makes less sense than the attacker not receiving rage.
Just edited my message missed something important which ginger also pointed out. Also, I was talking about the super charge bug which NW fixed on May-4-2020.