"Mabel! C'mon, it went this way!" Dipper shouted, running at full speed in pursuit of the gem monster they were pretty sure took a detour to the size-altering crystals, somewhere in the forest. He had foregone the safety of his weapon for speed, thoughts of how he would begin the soon-to-be new entry in the journal already fogging his head. As always.
His sister half-pouted as she easily kept up, even slowing herself down somewhat to remain behind her brother. It wasn't his fault – the sun shone high and mighty in the sky, as the day had barely passed morning. Mabel had her crossbow out and at the ready.
"Dipper, don't you think we should've waited for Grunkle Stan?" she shouted through the wind in her ears.
"Mabel, this is my chance to prove to him that I'm actually getting better at being a gem!" Dipper yelled back, risking a glance off his target to get eye contact. "Can't you please let me have that?"
A moment of silence followed, accompanied by a deadpan and an almost-stumble. Mabel stared incredulously, legs working on autopilot, dumbstruck at the puppy-eyed look her own twin was giving her. Now she knew half of how other people felt when they would do that, times two, to get what they wanted. The shock and humorous betrayal gave way as she internally reaffirmed the power twins had over people. Specifically, them over people.
Finally, she wrenched her gaze away, huffing. "I can't say no to that face," she sighed. "Fine. We've beaten gnomes, the Summerween Trickster, and Bill Cipher before. We can bubble one slightly big cat!"
Dipper crowed in excitement, pulling his sword out with a flourish. His hair whitened under his disappearing hat, his skin gained a bluish hue. He grabbed his sister's hand in happiness.
As if they'd done this a million times before, the twins started to glow brightly, until their forms had turned to nothing but pure light that started to come together, twirl in a diagonal dance, and merge -
A four-armed, four-eyed person, slightly taller than a full-grown adult, was formed, with a full circle gem of two complete halves glittering on their chest. They had jet-black skin and stark reddish-white hair that fell to their upper back in perpetually moving waves, dressed in a cross design made of shimmering, speckled material that could've easily been woven from the fabric of space and time itself, accented in complimenting neon oranges and blues. Their wide, bow-shaped mouth stretched to a happy grin at the harmony that they represented.
Eclipse ran in open-toed, lace boots, brandishing their rectangular glass shield, that they then threw under their feet and used like a hoverboard. In the light, the glass shifted colors, never settling on just one side of the spectrum.
The systemal fusion laughed, sounding doubly childish and doubly excitable. Two arms pumped the air.
"Imma come for you!"
-CP-
Introductions. I'm pretty sure the two groups of characters will be meeting next time.