The Great Rune Formation
Up high on the pedastle, Lilly was hovering in mid-air while closing her eyes. Many strange purple coloured symbols formed around her and soon got devoured by a green gem.
The green gem was embedded in a large Obsidian block that looked like as if it was sucking all the lights in. The green gem continued to devour the Runes formed around Lilly like a hungry beast, while Lilly continued to form even more ruins.
The Rune Formation was a big one, even for Lilly. The scale was huge and it required time and skills, which Lilly possessed. It wasn't hard per se but it was time consuming. The more complex the Rune Formation, the more time it'll take to form and to activate it.
Although the Rune Formation that she made wasn't a complex one, it was on a large scale which made the work of activating it time consuming.