from what i read online after you beat moms heart a beam of light is suppose to show up and take you to the Cathedral, but i just beat moms heart for the 2nd time and nothing showed up just the chest that ended the game for me
also i have the dlc
I would imagine you'd have to unlock all the endings before being able to access the cathedral (endings 1-11) but i'm not sure
False Hope is a Great Motivator ~ Futurama
You have to beat Mom's Heart 10 times to have a guaranteed run at Sheol/Cathedral. Until then, access to those areas works like a Devil Room spawn: if you don't get hit on Womb 2 (and to a lesser extent, no-hit on the boss) then you have a higher chance of the room spawning. If a God Room spawns you can go to Cathedral, if the Devil Room spawns you can go to Sheol.
Just keep playing and you'll get the ability to play Cathedral/Sheol as much as you want.
If you grab a Joker Card (Tarot/Pills slot), keep it until you reach The Heart and use it sometime during that floor. It will warp you directly to the Devil/God room and allow you to bypass the boss completely and head on down to Sheol/Cathedral. I'm not entirely sure if the Cathedral is an option at this point for you as it only ever gave me Sheol until I killed the heart 10 times.
Also, the beam of light seemed to happen at random - sometimes I would just get Sheol, sometimes both, sometimes neither.
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