Baeltar Scorchbeard

Combat Casting (3/day).  When Baeltar attacks with Ray of Fire, he can cast a spell of 3rd level or lower as a Bonus Action.

Legendary Resistance (2/day). If Baeltar fails a saving throw, he can choose to succeed instead.

Spellcasting. Baeltar is a 12th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 17, +9 to hit with spell attacks).  Baeltar has following sorcerer spells prepared:
Cantrips (at will): chill touch, friends, mage hand, message, produce flame, thaumaturgy
1st level (4 slots): burning hands, charm person, chromatic orb, shield 

2nd level (3 slots): darkness, detect thoughts, misty step, scorching ray

3rd level (3 slots): counterspell, fireball, hypnotic pattern

4th level (3 slots): wall of fire

5th level (2 slots): immolation 

6th level (1 slot): disintegrate

Multiattack. Baeltar makes two Ray of Fire attacks.

Ray of Fire. RangedWeapon Attack: +9 to hit, range 60/180ft., one target. Hit: 21(3d10 + 5) fire damage.