Obtaining Realmstones

Precasia Realmstone:
    Dropped from the Bush Baby, Stinger and Terradon.

Abyss Realmstone:
    Dropped from the Anemia, Bloodmist, Trickster, Slimer and Linger.

Haven Realmstone:
    Dropped from the Magicke, Goalby and Voliant.

Mysterium Realmstone:
    Dropped from the Bugeye and Fungung.

Deeplands Realmstone:
    Dropped from the Clown, Ghost, Faceless Runner, Shade, Trickster and Doubler.

Celeve Realmstone:
    Dropped from the Clown and Jumbo.

Gardencia Realmstone:
    Dropped from the Giant Slug, Dyrehorn and Sunny.

Immortalis Realmstone:
    Dropped from the Death Hunter.

Creeponia Realmstone:
    Dropped from the Host and King Creeper.

Iromine Realmstone:
    Dropped from the Dweller and Mechachron. Also drops as 
    Foraging loot at level 55.

L'Borean Realmstone:
    Dropped from the Treasure Box, Corallus and Neptuno.

Vox Ponds Realmstone:
    Dropped from the Flower Face, Squasher, Exoid and Pod Plant.

Barathos Realmstone:
    Dropped from the Bouncer, Eilosapien and Paladin.

Dustopia Realmstone:
    Dropped from the Hunter, Grillface, Shifter and Stalker Prime.

Lelyetia Realmstone:
    Dropped from the Grobbler, Seeker and Surveyor.

Ancient Cavern Realmstone:
    Dropped from the Automaton, Flower Face, Bloodsucker and Rock Critter.

Crystevia Realmstone:
    Dropped from the Case Construct and Construct of Mind.

Candyland Realmstone:
    Dropped from the Chocko, Sticky, Koko and Cherry Blaster.

Shyrelands Realmstone:
    Dropped from the Lost Soul and Stimulosus.


Teleportation to Greckon, Runandor and Lunalus

Greckon and Runandor portals can be found in the Mysterium dimension on the Portal Tower structure. 
You also need to buy Realm Travel Ticket from the Portal Master, which stands near the portals.

Killing Terrestrial in the Overworld will create a portal structure that leads to Lunalus. 
Terrestrial is a very rare mob that spawns during Full Moon Event in the Overworld.
