When this card is Normal Summoned, you can add 1 "The Agent" monster from your Deck to your hand, except "The Agent of Mystery - Earth". While "The Sanctuary in the Sky" is face-up on the field, you can add 1 "Master Hyperion" from your Deck to your hand instead.
Here are the monsters you can search with The Agent of Mystery - Earth’s effect. If The Sanctuary in the Sky is on the field you can search Master Hyperion.
Another thing when The Sanctuary in the Sky is on the field, you can Special Summon your searched The Agent of Entropy - Uranus or Master Hyperion. Use that monster with The Agent of Mystery - Earth to make a Synchro monster.
Ehhh, Venus for that purpose is highly questionable. There’s so much brick potential playing it as a “god card engine” and hoping you open up with exactly 3 cards you need out of 4 in your opening hand- while playing 3 dead draws in your deck