The last of the elves on Earth and one of the Merlins, Myrddin is one of King Arthur's archenemies. In the medieval
times, both Myrddin's armies and King Arthur would clash for the ownership of the Holy Grail. This dragged on till the 20th Century, where although Myrddin finally destroys Arthur's court, he is unable to find the grail, and thus threatens John Constantine to find it by taking his friend Rich the Punk and his family hostage. Myrddin in modern times appears as a politician and powerful rich man, using his powers to decimate Arthur and Constantine. Finally during a stand-off, John gives him a fake grail, which turned out to be holy poison that killed the elf.
First appearance in Hellblazer issue 110 and the main of antagonist of Last Man Standing.