Ok guys from what i've learned, rhinos can be very op at lvl 30 if you know how to use them. the build i am going to give out is a tank build and it use up alot of mana.

Str-108
Dex-37
Int-0

Armor-iceberg frost knight plate
Helm- get a vyxn or any pink helm level 27 or higher
weapon- preferably a lvl 30 reaper or else iceberg frosty hatchet
Shield- iceberg frost knight shield
ring- any ring that gives 5 armor or more

Skills-
6 vital force
6 guardian
6 stone skin
1 charge
4 restore
3 redemption
3 holy tempest

combo- first use ur buffs obviously
charge, redemption, heal, tempest and make sure your always close to them, don't let them kite you. if fighting birds and u get rooted make sure to heal to get free and if fighting mages same thing with frost. after using the combo i listed above try to use redemption then charge and then tempest because it will keep you close to them. if u die because of no mana then you're doing good cause u managed to tank them.

Thanks guys hope this helps!