What makes Kai'Sa Survivor strong? She's only 4 might, so when she's entering a contested battlefield with other friendly units, the opponent can just focus their damage to Kai'Sa anyways?

Kai'Sa, Survivor is considered a strong card primarily due to her ability to generate card advantage and her flexibility in how she enters the battlefield, rather than her raw combat stats.

While it is true that she has 4 Might and can be targeted by an opponent during a showdown, her strength comes from the following factors:

1. Card Advantage (The "Conquer" Trigger)

According to her card text, "When I conquer, draw 1." This is a powerful effect because it replaces itself in your hand. Even if she is killed shortly after, you have already gained a card, effectively mitigating the loss of the unit. As noted in RiftJudge FAQ #902, she must survive and remain on the battlefield when the conquer occurs to trigger this ability, but because she is a Champion, she is often played in decks designed to ensure she successfully conquers.

2. The "Accelerate" Keyword

Kai'Sa, Survivor has the Accelerate keyword, which allows you to pay 1 energy and a Fury rune to have her enter the battlefield "ready." This is a significant tactical advantage:

• Immediate Impact: By entering ready, she can participate in a showdown immediately upon being played, rather than waiting for a future turn or needing to be readied by another effect.
• Surprise Factor: You can play her into a battlefield that is currently being contested to tip the scales in your favor, potentially securing a conquer that the opponent did not anticipate.

3. Champion Synergy and Deck Building

As a Champion, Kai'Sa is often the centerpiece of a deck. Her ability to draw cards allows you to cycle through your deck faster to find your win conditions or defensive tools. Because she is an Epic rarity Champion, she is designed to be impactful.

Addressing your concern about "Focusing Damage"

You are correct that an opponent can choose to focus their damage on her during a showdown. However, this is often a "win-win" for the Kai'Sa player:

• Damage Mitigation: If the opponent spends their resources and damage to kill Kai'Sa, they are not dealing that damage to your other units or your base.
• The "Conquer" Priority: Because she draws a card upon conquering, the opponent is often forced to deal with her immediately. If they fail to kill her before the conquer resolves, you have already gained the card advantage. If they do kill her, they have spent their combat resources to remove a unit that has already provided value.

Summary: Kai'Sa, Survivor is not meant to be a "tank" that survives every combat; she is a utility-focused Champion that provides immediate board presence via Accelerate and consistent card draw via Conquer. Her strength lies in the fact that she forces the opponent to react to her, and she provides value even if she is removed from the board.