Maven is an NPC that can be encountered in a random map to unlock certain Atlas passive skills. You can also choose some other goodies, such as the infamous Maven Orb, so it's worth a try. When you fight with 3 map bosses, Maven will watch you, and if you finally defeat all these bosses, you will eventually be invited to join her cauldron. Let us see the complete process below.

First, you need to run the map until you encounter a specific NPC The Envoy. The appearance of this character is completely random, so you only need to run any map until the instance occurs. After you contact him a few times (4-5), the envoy will mention The Maven and she will observe you. Kill the map boss at that time and you will notice that The Maven is actually looking at you. After defeating the Boss, Maven will lose the "The Maven’s Beacon" you need to claim, which is a non-tradable task.

After completing all the above steps (this is the difficult part because it is completely based on RNG), go back to the hideout and add the task items found to the "map equipment". Doing so will permanently upgrade your POE Currency, allowing you to summon The Maven in other maps.

After that, browse any of our top-level maps. The "Call Maven" button will appear, and you need to Buy POE Currency to let Maven observe you. Fill out the map temporarily so that you can please her. When you kill the boss of the map, a message will be displayed on the map: "Maven currently owns the entertainment content of the boss of the map." This indicates that you no longer need to complete this mapping again.

Doing all of the above will trigger your atlas, which will show you which area you need to continue to interact with and kill Bosses so that The Maven can continue to follow you. The next step requires three bosses, and that is The Maven challenge. Kill the last of these 3 bosses and you will get an invitation. Pick it up and you will be able to proceed.