Summary
Light Cones are extremely important for any character’s build inHonkai: Star Rail. One of the main reasons why it’s crucial is the difference in the wielder’s performance during combat. Simply put, the better the Light Cone is, the more damage its user will deal.
When players are picking the best Light Cone for their characters, they have to fully understand their unit’s kit since it plays a major role in making a weapon works or not. For example, a 3-star Light Cone like Collapsing Sky performs much better than many 5-star ones for Blade.

S5 Effect
When the wearer defeats an enemy, increases ATK by 48% for 3 turn(s).
Best Wielder
Seele and Yanqing
SinceHunt units inHonkai: Star Railcan easily take out at least one enemy from existence, they’re able to easily activate the condition of Darting Arrow’s effect. Once they defeat an opponent, their ATK will be increased by 48%. Of course, for the character to take full advantage of such a powerful passive, they have to scale with ATK, or else the buff is worthless.

Additionally, it’s important to understand that although the ATK% buff is nice, the Base ATK stat of the Light Cone is weak. 4-star and 5-star Light Cones offer much more Base ATK, which makes them instantly better. But, as a last resort before getting a better weapon, Darting Arrow is a decent choice for Hunt units that scale with ATK% like Seele or Yanqing.
Argenti, Herta, Jing Yuan, Serval
Since mostErudition units inHonkai: StaR Railfocus on their Ultimate, Data Bank comes in to be a healthy pick for them if you don’t have a replacement. Even the Light Cone’s Base ATK is a little high compared to other 3-star Light Cones. The best character who can take full advantage of Data Bank is Argenti, since he heavily relies on his Ultimate to deal damage.
However, even if a 56% damage increase sounds nice, the Light Cone still suffers from low Base ATK and it’s better to replace it with a 4-star or 5-star one if you’re planning to maximize the damage of your unit.

Upon battle entry, all allies receive 20 increased SPD for 1 turn(s).
All Harmony units
Having your entire team get an SPD head start over the enemy is crucial to make them start attacking first, especially if you’re running some slowpokes in the team. Additionally, mostHarmony units inHonkai: Star Raildon’t scale their buffs with their stats, so the low stats on the Light Cone don’t hurt them that much.
Increases DMG dealt from its wearer to Slowed enemies by 48%.

Welt and Silver Wolf
WhileNihility users inHonkai: Star Railcan do so much more than just slowing enemies, 3-star Light Cones don’t really offer better than what Loop has in its passive. Dealing 48% extra damage to slowed enemies can be massive. Welt and Silver Wolf are the perfect choices to use Loop since they’re able to slow enemies. However, it doesn’t have to be a Nihility unit to slow opponents. As long as the monster is slowed, Loop’s effect will be triggered.

Increases the wearer’s Basic ATK and Skill DMG by40%.
Blade, Imbibitor Lunae, Hook, Trailblazer
Having their Basic ATK and Skill DMG increased by 40% when using Collapsing Sky is a crazy enhancement for allDestruction units inHonkai: Star Rail. What’s even better is a character like Blade that doesn’t fully scale with ATK% and leans more into HP% can really benefit from what Collapsing Sky has to offer. The Light Cone also works on characters like Dan Heng, Hook, and Trailblazer.
After the wearer uses their Basic ATK, their next action will be Advanced Forward by 20%.

Bailu, Luocha, and Natasha
Nothing better than making theHealer able to continuously play inHonkai: Star Rail. Multiplication definitely helps in that regard since it constantly Advances Forward the actions of Abundance units. Additionally, the Light Cone’s Base HP is high for a 3-star weapon, which is very convenient for most healers who rely on their HP to heal during combat.

Increases DEF of its wearer by 32%. If the current HP of its wearer is less than 50% of Max HP, increases DEF by an extra 32%.
Gepard, March 7th, and Trailblazer

As a Preservation Light Cone, Amber offers a decent amount of Base DEF. Not only that, it further buffs DEF% by up to a whopping 64%, which can be extremely useful for anyPreservation unit inHonkai: Star Rail, especially those who grant shields based on DEF.
