Okay, so eram's most certainly the strange someone jevil met. Since they have a lot of similarities, they see reality as a game, throw bombs, are demonic, spit projectiles and love violence, while jevil's scythe is called "devilsknife" and the shadow mantle was present in chapter 1.

Eram is heavily associated with knives, they themselves say the famous line. Aqua, which has unique similarities to eram in particular and references jevil uses knives. And "scythe" may not necessarily mean scythe, as sheary in chapter 5 has that element even though they are shears. So, the death/scythe elemental pair that spamton warns you about has to be attributed to eram. Again, he mentions cat/puppet casually, but death/scythe is "watch out" and "never again" which might mean that someone with the elemental pair of "death/scythe" is spamton's caller

And then there's the tail of hell which is usually attributed to friend because cat petterz had cats be made of circles. However there's organikk dialogue that spells out "the tale which must be followed" and there's one that goes "the tail which must not be followed", so the tail must be going against the prophecy, which is just the weird route, and at this point the weird route is synonymous with eram. And also cat tails are not pointed, demon tails are. 

But the tail of hell is related to dess' disappearance since children followed the tail where the forest would grow and the words are mixed up, which is related to the egg man, who is kris' trauma. And the knight wields a knife too, which opened the dark world in "that incident"

It all points back to eram

Okay, so eram is jevil's strange someone, spamton's caller, dess' tail of hell, anything else? Or is that all we need to start calling her the mastermind of deltarune?(Read body)