Base Class: Barbarian
The Path of the Totem Warrior is a spiritual journey, as the barbarian accepts a spirit animal as guide, protector, and inspiration. In battle, your totem spirit fills you with supernatural might, adding magical fuel to your barbarian rage. Most barbarian tribes consider a totem animal to be kin to a particular clan. In such cases, it is unusual for an individual to have more than one totem animal spirit, though exceptions exist.
Spirit Seeker
Yours is a path that seeks attunement with the natural world, giving you a kinship with beasts. At 3rd level when you adopt this path, you gain the ability to cast the beast sense and speak with animals spells, but only as rituals, as described in the Spellcasting section.
Totem Spirit
At 3rd level, when you adopt this path, you choose a totem spirit and gain its feature. You must make or acquire a physical totem object that incorporates a part from the totem animal. At your option, you also gain minor physical attributes that are reminiscent of your totem spirit. For the Otter totem, it might be webs between your toes and fingers or a light coating of fur all over your physical form.
Otter
While raging, you gain a swim speed of 25 feet. Additionally, you can hold yor breath underwater for a number of minutes equal to 1 + your Constitution modifier + your proficiency bonus. The spirit of the otter empowers your lungs.
Aspect of the Beast
At 6th level, you gain a magical benefit based on the totem animal of your choice. You can choose the same animal you selected at 3rd level or a different one.
Otter
You gain the eyes of an otter. If you do not have dark vision, you gain darkvision to a range of 30 feet. If you have dark vision already, your range extends by 30 feet. The otter spirit blesses your eyes.
Spirit Walker
At 10th level, you can cast the commune with nature spell, but only as a ritual. When you do so, a spiritual version of one of the animals you chose for Totem Spirit or Aspect of the Beast appears to you to convey the information you seek.
Totemic Attunement
At 14th level, you gain a magical benefit based on a totem animal of your choice. You can choose the same animal you selected previously or a different one.
Otter
While you are raging, if you make an unarmed strike against a target, you may take two attacks, one with each hand, empowered by the spirit of the otter. These attacks count as claw attacks and deal 1d4 + your Strength modifier slashing damage. These attacks count as magical for purposes of overcoming resistances to non-magical weapons.
I'm putting together an otter-themed campaign right now... this one is gonna be fuuun to use :)
Note that in order to share this I could not map beast sense to the class. You'll need to create a private homebrew feat to add the Spirit Seeker spells to your Barbarian.