Knockdown
From Eldfall Chronicles
A model that suffers a Hit with this Trait becomes Crouched (State). It does not affect models two or more Sizes larger than the attacker.
Community Answers (Discord)
Q: A model shows "Knockdown X", but the rules have no X value for Knockdown. What's correct?
A: The description should simply read Knockdown — the "X" belongs to the Fencing IV combat art. Treat it as plain Knockdown. (— meksmaks)
Q: If I hit my Target (A1) and also hit A2/A3 with the same attack, do they all get Knockdown?
A: They are Hit by the attack, but only the Target (A1) is Hit with Knockdown. With a Targetless weapon you can't apply Knockdown at all, since you'd be "tripping" the point used for Targetless rather than a model. (— Dockel)