Elden Ring may have been out for four months already, but new players are still discovering the game every day, and even those who have played it for a while are still encountering the Great Rune boss fight with 
Rennala, Queen of the Full Moon, for the first time.
When coming up against one of the game's most difficult bosses, several players have turned to their fellow Redditors for tips on how to defeat her. Ten Redditors who prevailed shared their methods for winning the battle, allowing other players to learn plenty of options for success.
Summon wolves after first Phase 2 attack
Elden Ring's wolves can be quite powerful allies to summon during a fight, but Redditor Azuillian recommends holding off on spirit summons at the start of the battle. When players do, they should use wolves, and "Summon [them] dodging her first attack in phase 2."
Using the summon does consume 55 Focus Points, and considering that the original poster was using a Glintstone Mage build could possibly consume more, so it's critical that they be used at the right time, or else the resources expended are essentially wasted.
Use a tankier summon than wolves
Of course, the wolves aren't known for being Tank summons, and Some-Scheme838 points this out as their weakness, recommending that players should go with "a tankier summon" than wolves, as using wolves was the main focus of the original poster's strategy. An example would be Mimic Tear.
Scheme also notes, though, that "[they] had help" when taking on Rennala, indicating they beat her in co-op mode. The thing is, Rennala isn't an Elden Ring boss better in co-op, like Mohog. She can definitely be handled solo, but a tankier companion could still aid that, even though Scheme doesn't recommend any particular ones.
Mix sword spell with actual sword
There are several swords among Elden Ring's best weapons, and jjshotgun said that for their successful defeat of Rennala they "used the sword spell along with an actual sword" to take her on, mixed with a "melee summons" of Banished Knight Oleg.
While there's no specification about which sword spell was used, this combination does provide a nice mix of mage and warrior for the character, allowing for longer-range and melee attacks simultaneously. Rennala's fight, like many other bosses, requires flexibility, and this tactic meets those needs.
Summon Oleg right before Phase 2 starts
It's telling that jjshotgun isn't the only one who recommends using Elden Ring's second-best spirit summon, Oleg the Banished Knight, as part of the strategy. SaneManiac741 is more specific on when to use Oleg, though: "Try using Banished Knight Oleg right before the start of phase 2."
As the explains in a follow-up comment, players also need to restore FP after summoning Oleg, so summoning him when she's so weakened means it's easy to transition into the next stage with full FP and Oleg at full health, the most ideal circumstances when employing the FP-costly spirit summon as backup. Players just need to ensure the restraint of not ending Phase 1 prematurely.
Claws will deal heavy damage
The Marvel Comics character Wolverine may not be part of Elden Ring's world, but his claws inspired dingdongdiddles to call the game's Claws "wolverine gloves." The comparison makes sense, though, since "the claws messed her up" and the Redditor was only "level 35-38ish."
The Bloodhound Claws have the most effective damage of all claw types, but unlike the others, it requires 5 Focus Points as opposed to the others' three, in order to unlock the Bloodhound's Step skill. Still, it's worth the drawbacks and extra effort, including but not limited to this fight.
Use night maiden's mist
Rennala is "a great target for 
Night Maiden's Mist," according to mistakai, as long as players don't melee-attack her, which means that she'll remain still and be an easy target for this. Players need to ensure they're in range, though, since the mist only damages what it touches.
On top of that, it's important to note that this ability won't be available unless players have already completed Gowry's quest line. It's unlikely players would go in there expecting to use it without it having been mentioned before, and it's also very likely that it's already been unlocked by players at this point. Gowry's quest is worth completing for its own sake, though, so it's worth doing it for the unlock, too.
Rolling away works for several attacks
Just as rolling and dodging help defeat Elden Ring's Malenia, so too do they play a major part in defeating Rennala. Sometimes, avoidance is the most strategic option. Metaspark gets quite specific: roll "left to avoid the laser," "away from the moon to avoid its explosion," and "forward to avoid the homing bolts" after running left.
Preserving health is even more critical on a single-player fight, and Metaspark's recommendations do just that. Even if it's hard to memorize, players can keep as much in mind as they can while learning the patterns to avoid on their own. Rolling is also more beneficial the less amount of armor and weapon weight players have equipped.
Focus on stats other than magic defense
RMHaney warns: "Don't worry about magic resist; it won't make enough difference and [players] sacrifice other stats" that could make more of a difference in the combat. Rennala's magical abilities are too powerful for resistance. Instead, it's better to be proactive before she can summon, they recommend.
Aggressive play isn't the only way to handle Rennala, so players who are prepping for battle don't have to take the second part of that strategy into . There's also longer-range attacks and summoning to utilize. No matter their level and build, or play style, players just shouldn't put their efforts into what will ultimately lead to nothing in the fight.
Don't attack during her spell barrage
Because her magical abilities are so powerful, it's also important that players "dont attack her when shes just released one of the slow barrage of spells," Redditor Danubinmage64 points out, as it will deal damage to players while providing no benefits.
The benefit to being patient, which is ultimately Danubin's big takeaway, is that opportunities will open up for players to attack her in more fortuitous ways. Like the Souls games that fromSoftware also developed, sometimes it's about waiting, or even learning from the failure of a certain strategy, as opposed to just going in "guns blazing," so to speak.
Rock sling is easy and effective
The most common suggestion for the fight, though, was the rock sling maneuver. Whereas many who recommended its use also combined it with another weapon, Hctaz emphasizes it on its own: "Rock Sling is a fairly easy to snag spell that does physical damage and will really help you deal with this fight."
Rock sling allows for ranged attacks, and as Hctaz says, is pretty easy to obtain. It lies in a cellar chest located north of the Street of Sages Ruins, and is minimally guarded by Servants of Rot. This makes it an especially beneficial tactic to use for players who end up fighting Rennala at lower levels.
