Vielleicht kommt diese Waffe in einem späteren DSA Abenteuer zum Einsatz, aber hier erst mal die Systemkonvertierung.
Prinzipiell handelt es sich einfach um die elfische Version der bekannten Zweililien.

A Fasanja'tlinc is a double weapon. You can fight with it as if fighting with two weapons, but if you do, you incur all the normal attack penalties associated with fighting with two weapons as of you were using a one-handed weapon and a light weapon.
This weapon can't be used effectively in one hand.

Because of the two hooks under the primary blades, you get a +2 bonus on your opposed attack rolls, when attempting to disarm an opponent (including the roll to avoid being disarmed if you fail to disarm your opponent).

You can use the Weapon Finesse feat to apply your Dexterity modifier instead of your Strength modifier to attack rolls with a Fasanja'tlinc, provided you're at least Medium-size and proficient with the weapon (DM may decide that elves of certain communities or regions automatically are proficient with this weapon instead of the longsword or rapier).

Weapon Cost Damage Critical Range Increment Weight Type
Fasanja'tlinc 90gp 1d6/1d6 19-20/*2 - 14 lb. Slashing

The Fasanja'tlinc is a large exotic weapon, except for elves, for whom it's a large martial weapon.