Description

In the claimThrone() function, the intended behavior is to reward the previous king with a portion of the fee when a new king claims the throne. However, no such transfer occurs — the amount (previousKingReward) is hardcoded to zero:

This results in no ETH being sent to the dethroned king, violating the game's fairness .

Risk :

• Medium

Likelihood:

• This occurs every time a new player successfully calls claimThrone() and becomes the king.

• The previous king is always denied the expected compensation, which can be easily observed on-chain and exploited to game the system.

Impact:

• Violates game fairness. (no incentive to be king).

• Reduces trust in the system for real users.

• Enables malicious frontrunning behavior — attackers can grief by repeatedly stealing the throne without loss.

Proof of Concept

• Assume player 1 is the currentKing

• player2 came and claim the throne

• there is no tracking of sharing portion to previous king its hardcoded to zero;

Further issues :

• Previous king receives nothing:

  • previousKingPayout = 0, and no transfer is made.

  • This breaks the incentive loop that is core to the throne game design.
    
    

• Platform receives nothing:

  • currentPlatformFee = 0, and is added to the platform balance.

  • The code contains a dead check:

    if (currentPlatformFee > (sentAmount - previousKingPayout)) { currentPlatformFee = sentAmount - previousKingPayout; }
    
    * Since both variables are `0`, this check **never triggers** and is **meaningless**.
    

• Pot receives all the ETH:

  • amountToPot = sentAmount - currentPlatformFee → always equals full sentAmount.

  • This causes the pot to grow unnaturally fast with no real fee deductions.

Recommended Mitigation

• Add logic to give incentives to the previous king

• Remve Hardcoded currentPlatFormFee