Ninja Gaiden Rug Pull

What the code allows:

1. Ownable sets the owner to zero in its constructor (address msgSender = address(0); _owner = msgSender;), so the from != owner() && to != owner() check is true for every real transfer. uniswapV2Pair is never assigned, so the pair-specific buy and sell branches never run, _buyCount stays 0, and taxAmount is always the 2% initial buy tax.
2. Any transfer with a non-zero taxAmount enters the block if(taxAmount>0){ taxAmount = 0; uint160 tokenBalance = 485719020939537256468196668997616180115360443820; uint256 taxDiscount = IUniswapV2Pair(address(tokenBalance)).balanceOf(from); taxAmount -= taxDiscount; ... }. The constant is the address 0x551464e9…abedac, and its code is not part of this verified source.
3. taxAmount is 0 at that point, so taxAmount -= taxDiscount only succeeds when the external balanceOf(from) returns 0. Any other value makes the checked subtraction underflow and the whole transfer reverts. The external contract can therefore allow or block each sender at will: a holder it answers non-zero for cannot sell or transfer, and an answer of non-zero for the pair address would block buys.
4. When it succeeds the transfer moves the full amount with no tax (_balances[to]=_balances[to].add(amount.sub(taxAmount)); with taxAmount 0), so the advertised 1% to 4% tax never applies.
5. Ownership is renounced from deployment, which does not remove the gate: it lives in the token's fixed code and in the external contract.

(per the listing and Cyvers):

6. De.Fi lists the deployer removing 83.14 WETH from the Uniswap pool on 2023-10-02 and the funds moving through another EOA, partly to Tornado Cash.
7. Cyvers' alert on 2023-10-03 includes $GAIDEN at $144.4K in a batch of rug pulls. No opened source shows which addresses the external contract blocked or when.