How to defeat Astel Naturalborn of the Void in Elden Ring

sportskeeda.com:

There are plenty of side bosses in Elden Ring, but not many of them reach the scale that Astel Naturalborn of the Void does within the underground section of the game. Players who have been following the questline with Ranni will be in for quite the fight against the Void.

The questline with Ranni will eventually bring players to the city of Nokstella, which is a counterpart to Nokron. Exploring the area exposes new sites such as the Rot Lake as well as new enemies like Astel. Players will likely have seen enemies that resemble the beast in prior underground ruins, but nothing to the same magnitude of power.

To even begin the fight with Astel Naturalborn of the Void, players must get beyond the Scarlet Rot Lake in Elden Ring. If the river is followed to a coffin at the end of the red lake, then they will be taken to the massive cosmic lair of the creature. In the massive area, players should prepare for some serious scale.

Tips for Astel Naturalborn of the Void:

With the creature down, players will get a hefty reward of 80,000 runes. But it's the door behind the boss in the massive arena that is more enticing.

Through the Ranni questline, players can earn the Carian Study Hall key after they get the Fingerslayer Blade. Completing the Carian Study Hall will essentially unlock Renna's Rise, which was previously locked by a blue door.

If players head to the top, they will find a portal that takes them directly to Nokstella. The path can then be taken through the old city to reach the Lake of Scarlet Rot, and eventually, the void boss at the end.