Irelia should be listed as a rival for Kindred

Despite common perception, Irelia is not a lich. You can check the wiki, the only similarity she shares with a lich is the fact that her soul remains outside her body, residing and animating her blades, similar to a lich's phylactery. However a very important part of being a lich is being, you know, dead. Irelia never died in her lore, her life was fading and she was on the brink of death but she never died. So by all means, she's alive, sort of. It's an odd state for sure, but shes not a lich.

While I'm a fan of the whole 'good Lich' idea that the setup can imply, it's too troublesome. Fulfilling the Lich archetype for Irelia would radically warp her character away from everything she is currently (or can be). We're talking 'full move over to the Shadow Isles' level redesign. Suffice to say, she probably came close or did die, but returned through Soraka's magic, her soul becoming displaced. The energies of life are still with her, though.

Indeed....

But what are your thoughts on X ?

In original concept, for being lich you should have to accept being lich other wise you basically die. That means you can't turn to a lich with enforce (Expect Warcraft who includes liches that turned with enforce by Burning Legion's second commander, Kil'Jaeden. And may be more universe that I don't know). But it's not one of the main features for being lich. So it can be change. As other members said, Irelia didn't die. It is like Voldemort. Voldemort didn't die, that's why we can't say he is a lich, as well as Sauron. You have to die and your entire soul (not like Sauron) must be left from your body.

Also last but not least, for turning to a lich, there should be a ritual.