'Hehe. It is you.
You are the villain behind the scenes.'
Alephee said something mischievous to Eren without alerting Nira Nightshade. Incidentally, she wasn't in her pendant abode. She was exploring the Sage's Abode while the latter was busy talking with Eren.
***
Eren couldn't deny Alephee's "accusations".
The Osan Woods' Butcher fiasco served as the spark to light the fire that already existed between the two kingdoms. He then injected massive amounts of weapons and potion bombs into the open market - supplying both sides with weapons to fill up the White Raven Guild's coffers.
The butcher appointed Kaalmahen to act as his proxy to form a supply-and-distribution chain inside the Badlands. He supplied the kingdom of Layos directly. He also used Serius Fenris' connections to supply other establishments as well– arming anyone he could find to their teeth.