How do you unlock Cerberus' heart?

[ZKusand]

Everyone is saying you just pet him 20 times, but I've pet him at least 30, probably more like 40 and nothing

[The North]

i didn't get the achievement till i left the room / entered the bedroom

[Lorska]

Achievements are almost always checked upon loading transition, so anytime the game saves.
If something doesn't pop but you feel it should, change rooms.

[Nibbie]

He is asking about the *heart*, not the achievement. It is petting, but if I remember correctly it only counts pets after you maxed him, and like most story progress you have to do a run to 'refresh' the House to get the dialogue.

[ZKusand]

Nibbie is right, I've got the achievement already, just after the heart, but thanks anyway.
As for your advice Nibbie, I've tried petting him 20 times in a row now that I've got full hearts and still didn't unlock even after completing a run. Guess I just need to keep running and cross my fingers for the right conversation to come up. I'm in a similar situation with Poseidon and Ares

[Tora]

damn im 4 years late. but beat extreme measures on max ( hades 3 boss phase). then you get the dialogue with cerberus

[James Rye]

After you maxed out the hearts and get the little chibi avatar next to the keepsake, does it do anything? I saw videos with a huge Cerberus running at Bosses yet it didn't seem to trigger for me or I have no idea on how to trigger it.

Or is it just cosmetic bs that doesn't help me in my encounters/boss fights? I really wanted a three headed attack hound for the boss fights....

[plump pickle]

Originally posted by James Rye:

After you maxed out the hearts and get the little chibi avatar next to the keepsake, does it do anything? I saw videos with a huge Cerberus running at Bosses yet it didn't seem to trigger for me or I have no idea on how to trigger it.

Or is it just cosmetic bs that doesn't help me in my encounters/boss fights? I really wanted a three headed attack hound for the boss fights....

Probably should've made a different thread for this since this one is old. But to answer your question, the chibi avatar is just to tell you that you maxed out the relationship with whoever you got the keepsake from.

And the Cerberus you saw running is only for EM4 Hades bossfight. It's his though, not yours.