Wow this is seriously cool...I love the way the lining works.

Do they get tired of jokes relating Aru's name to a howl?

Aru himself is also an anthro jackal, and he DESPISES name jokes. :D

The angels are pretty apathetic about it. In fact, they generally have the personality of a ragdoll overall. Unless Aru has given them specific instructions, they just casually play along with anything that happens, whether it be a child touching them out of curiosity, or someone setting them on fire. If they're experiencing too much pain or stress, they just vanish in a puff of smoke.

God of Jackals and Blades, dude. :D There are two reasons Aru went with sword-shaped money:

1. Being a God of Blades, Aru is capable of effecting various miracles involving blades, such as creating and destroying them at will. Since these coins are blades, this allows Aru to create and destroy them, as the owner of an entire currency ought to be able to do.
2. In Aru's opinion, sword-shaped coins are cool as heck, and who cares that they'll destroy whatever coin purse you put them into.

It occurs to me that with a big enough coin, certain problems could be solved by literally throwing money at them.

Oh man, I never thought of that. That's hilarious. :D