How about some more fun for DnD 5e?

 

College of the Crossroads

You might have been the best there was or you might not have been able to pluck a string, but boy after the man or woman in black met you and tuned your fiddle at midnight at the crossroads, you became a titan of stringed instriment.  You made a deal or maybe you won a contest, but either way, you have powers most didn’t think possible all at the low cost of having to watch your back for the rest of your days lest someone come collect

Bonus Proficiencies

When you join the College of the Crossroads at 3rd level, you double your proficiency for any stringed instrument you use.  You also gain proficiency in arcana and religion if you were not proficient in those or you gain proficiency in another skill for each one with which you were already proficient.

Fiddle of Gold

Also at 3rd level, you learned to summon an instrument you got from the man in black.  The instrument is a golden stringed instrument that always is immaculate, has perfect pitch and counts as a +1 magic club for any melee attacks you make with it.  It can be used as a focus for any spells you cast giving you a +1 bonus to your DC and to any spell attacks you make with it.  At level 11, these bonuses becomes a +2, and at level 17 these bonuses becomes a +3.  You can dismiss the resummon the instrument as often as you want as a bonus action.

Dark Songs

Starting at 6th level, you’ve learned more from your former master.  You gain access to warlock spells when you gain new spells or the chance to replace a spell, but you may not know more than four warlock spells.  These spells count against your normal number of spells.

Hounds of Hell

At 14th level, the devil begins to claim his due, but you’ve becomes a silver tongued fiend in your own right having mastered the first monsters sent to collect you.  Once per day, you may as an action summon three hell hounds.  These creatures obey your commands, but you must use a bonus action each turn to direct them or they act according to their own interests.  If they die or are dismissed as an action, you can resummon them again after a long rest.

 

 

 

Thoughts?