As the Earth-elemental Fiend, he drains the power of the Earth Crystal, making the Earth rot in Melmond. He was the third fiend to awaken, doing so shortly before the game begins. When the Warriors of Light arrive at Melmond, they find the Earth rotting and people dying. They learn that a vampire is blamed for this occurrence, so they travel into the nearby Cavern of Earth to defeat it. However, when they return to the town, they see that the Earth is still decaying.
Using the Star Ruby found in the cavern to gain passage through the Giant's Cave, they travel to the Sage's Cave, where they are told by Sadda that the vampire was only working for a greater force; Lich. The Warriors travel again to the Cavern of Earth, where they find the Earth Crystal. After confronting Lich, the party prevails. The Earth Crystal shines again, and the land stops rotting, growing again by the Crystal's power.
Lich is a difficult boss, the hardest boss faced at that point in the game. As an undead enemy, he is weak to Dia and Fire, so if either of these spell series are available, their use would prove better than mere physical attacks, which are not too effective, but if one uses physical attacks, they should be augmented with the use of Temper.
He is a proficient user of elemental spells and can complement his physical prowess with Haste, as well as hinder the party with Sleep. The party should Heal whenever weakened while keeping on the attack. With this method, this battle won't stage a serious difficulty at all.
Even though Lich was defeated, when the Warriors of Light travel through time, they must fight the Lich of the past. Inside the Chaos Shrine, there is a floor known as the "Lich Room" which contains many of the monsters from the Cavern of Earth. The stairway to the next floor is guarded by this past Lich, an encounter which can be triggered many times by walking through the same spots.
This time, however, he has more HP than last time, and an expanded spell list, including Death and Flare. The same tactics from the previous battle work here, with the Firaga and Diaga spells effective against the still undead Fiend. Even physical attacks can prove to be a major help against Lich, by augmenting physical attacks with Haste, Temper and Saber.
It is interesting to note that the Lich is the only Fiend who does not talk to the party before fighting them. The same also occurs when it reappears in Final Fantasy IV: The After Years. In the remakes however the Lich does talk to the party before fighting them.
The Lich also makes a major appearance in the Final Fantasy parody webcomic 8-Bit Theater, where he serves a similar purpose to that in the game as one of the Four Fiends, and guards the Earth Orb from the Light Warriors.
Due to a bug in the PSP Version of Final Fantasy, if the game crashes while in the Lich fight, more Liches may spawn. This may also happen if Final Fantasy is closed during the Lich fight. This can cause problems with leaving the cave.