Hypothetical

[L]

Say I have a card like:

•Thorongil, Aragorn
Companion • Man
etc

Can I use the "sub-name" to be spotted for various things? Such as having it bear Ranger's Sword, Blade of Aragorn? Similarly, would this work with non-specific names? Such as having a say like: Bearer must be Lady of Light.

[TelTura]

Sub-titles are only used for uniqueness purposes and cannot be spotted or otherwise used...the example usually used is Ulaire Attea, The Easterling.  He's not an Easterling, you can't use him as a requirement for spotting an Easterling, etc. 

Now, if you were to create a card that said something like "Bearer must be Galadriel, Lady of Light" that would be permissible, if incredibly narrow.  I suppose you could even stretch that to "Bearer must have sub-title of Lady of Light", but that's kind of awkward.

Like I said, there is no use within the game for subtitles, outside of reference purposes for players to differentiate different versions of unique cards.