Void Vessel (Normal) or Void Vessel (Hard)?

[Chrommanito]

What's the difference between Normal or Hard? how differ is the reward? why shouldn't I grind the dog on Normal instead of Hard?

[QuaestComm]

Only the Hard variant has tier 4 containers for both Keelan and Hagios Sheepdog (tier 4 containers have the best drop rates for their codes specifically), and hidden room containers on Hard drop a lot more research materials as well. Also, you get 6 keys per win on Hard, vice only 4 on Normal.

That said, I managed to get everything I needed for research while going for the 100 Normal mode wins title, so don't feel compelled to go for Hard if you're not quite strong enough for it just yet.

[Hades™]

i suggest to run normal rush to boss and keep the keys, then after u gather for example let's say 30 keys , switch to hard and open all the containers there . so
: Farm keys on normal mode
:Use ur keys on hard mode

[Dudlios]

Hades pretty much gave the answer how I farm Void Vessels. Get keys on normal difficulty, completely ignore the chests on normal, their drop rates aren't very good. EXCEPT for broken chests because you don't need keys for them. Not required but those extra resources helped me to make upgrades for fellow doggo early on before i eventually got doggo.

Then do a hard when you got decent amount of keys, but don't worry too much to complete it, your focus there is to just open chests.

Managed to get fellow doggo before his Christmas gifts expired with that strat. I lost sleep there because the christmass gifts REQUIRED fellow doggo to be owned in order to be redeemed. But I got doggo hours before the gifts expired. I did eventually buy fellow doggo bundle which is automatically discounted if you own doggo. So even if you are thinking about buying a doggo bundle it will help a lot to grind and unlock doggo before you do that. It will literally save you money.

[Geardo]

I got all parts for Keelan and doggo on Normal since I was not able to grind Hard for a while

Now I do what Hades said though I am questioning the drops for food parts, something odd going on there especially with Genetic boxes in either mode

[ShinRasKemo]

Just use the weapon Voltia and the Endboss on hard is easy, when u have to destroy it's shilds.

Like the others said:
Normal is very easy, but less loot.
Hard is a little harder, but more loot and Endboss is easy when u have Voltia.