Constellar Kaus is a pretty solid card for a growing Archtype.  Light is excellent, Beast-Warrior is...not bad.  Strange for the Constellar theme, but not useless.  1800 attack makes him a reasonable attacker, although the 700 defense isn't great.  He doesn't do much, but his effect is useful.  Up to twice a turn, you can use either effect here...targeting a Constellar Monster to increase or decrease its Level by 1.  So target two Monsters, increase or decrease each by 1, or one of each, I mean it's screaming for XYZ abuse.  I'd play at least one in the Deck, maybe two.
 
Ratings:

Traditional:  2.5/5 
Advanced:  3.5/5 
Art:  5/5 

Today we are looking at: Constellar Kaus

“Cannot be used as a Synchro Material Monster. Up to twice per turn: You can target 1 "Constellar" monster on the field to activate 1 of these effects;
● Increase its Level by 1.
● Reduce its Level by 1.”

This card is pretty cool; it not only has a nice effect for an xyz deck, but also has all the right typing. Light gives you access to honest, beast-warrior gives it search ability via Fire Formation Tenki, and Constellar name rounds him out to a great themed support card. The stipulation of not being able to synchro summon with him is not terrible, Constellar’s are mainly an XYZ deck anyway. I really want someone to make a tier-1 Constellar deck. Will it happen? I hope so.

Bottom line: Play it in anything you need a normal summon-able level 2/3/4/5/6. (His effect can target himself, of course.)

Advanced: 5/5 (his typing and great effect make him highly splashable.)
Traditional: 3/5