Ethereum killer is only just a term by the people that think this xxx coin can kill eth because it can function almost the same as eth but only they have a little advantage. The truth is there is no such thing as ethereum killer because eth is like bitcoin. These two coins are the base of all cryptos. Have you seen a coin so far that beats bitcoin? I bet none. The same thing also applies with eth.

Until now eth was still standing peacefully on the second spot and as you can see almost 70-80% of the projects up to this date are still relying and using the technology of eth. There are alternatives to eth like matic and bsc but they are only good for this (as an alternative) don't expect too much on them.