1 3ds/2ds (no matter the size or color)
1 copy of Fire Emblem: Awakening
1 clock(haven't tried with digital)
1 dagger (or any blade really)
At least more than 10 feathers
41 minerals or rocks or gems(either or will do, gems for the best result though)
Arrange according to the picture, please note that there will be two instead of 3 rocks/minerals/gems between the statue and the dagger(or what you decide to pick) and there is a line of the rocks/minerals/gems between the clock and the statue(it's hard to see in the picture)
Keep in mind you'll need to set the statue in last and mind your distance. Choose your words carefully when process is complete.
**WARNING**
I'M NOT HELD LIABLE FOR ANY DESTRUCTION, MASS GENOCIDE OF THE HUMAN RACE, POSSESSIONS, DEATHS, INJURY, PSYCHOLOGICAL TORMENT, OR ANYTHING THAT COULD BE DEEMED HARMFUL BECAUSE OF THE PROCESS OF SUMMONING OR GRIMA IN GENERAL
This humongous centipede like dragon requires care and is practically a living fossil being an earth dragon.
With that in mind Grima can take a human form, but you'll have to persuade the dragon( I advise taking professional classes to boost this skill to the max) and from there you can take care of the Fell Dragon as if the over grown reptile was a human being.
Bringing up Naga at all costs
Questioning several times within a short period
Complying with any demands set
Actually using the Fire Emblem in place of the statue to summon Grima