Bond of Battle

You harness the heat of battle to forge a magical bond between yourself and one willing creature you can see within range. For the duration, while you and the target remain within 10 feet of each other, you each have the following benefits: 

• You gain 5 temporary hit points at the start of your turn.
•  You can't be Flanked, if using the optional flanking rules. 
• When you make a weapon or spell attack against a target while Flanking it with the other creature affected by this spell, add 1d4 fire damage to the attack or to one damage roll of the spell. 
• You have advantage on saving throws against being charmed, frightened, pulled, or pushed.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the temporary hit points increase by 5 for every two slot levels above 2nd, and the added fire damage increases by 1d4 for every two slot levels above 2nd.