diff --git a/contracts/CryptoHero.sol b/contracts/CryptoHero.sol
index 073ee90..b53fa5b 100644
--- a/contracts/CryptoHero.sol
+++ b/contracts/CryptoHero.sol
@@ -13,6 +13,8 @@ contract CryptoHero is Ownable, IERC721 {
 
   uint256 public gen0Counter = 0;
 
+  uint256 initHeroPrice = 0.01 ether;
+
   bytes4 internal constant _ERC721Checksum = bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"));
 
   bytes4 private constant _InterfaceIdERC721 = 0x80ac58cd;
@@ -38,7 +40,9 @@ contract CryptoHero is Ownable, IERC721 {
 
   mapping(address => mapping (address => bool)) private _operatorApprovals;
 
-  event Birth(address owner, uint256 heroId, uint256 mumId, uint256 dadId, uint256 genes);
+  event HeroBirth(address owner, uint256 _heroId, uint256 mumId, uint256 dadId, uint256 genes);
+  event HeroEvolved(uint256 indexed _heroId, uint256 _oldGenes, uint256 _newGenes);
+  event HeroRetired(uint256 indexed _heroId);
 
   constructor(string memory dname, string memory dsymbol) {
       _name = dname;
@@ -54,10 +58,18 @@ contract CryptoHero is Ownable, IERC721 {
       return (_interfaceId == _InterfaceIdERC721 || _interfaceId == _InterfaceIdERC165);
   }
 
-  function createHeroGen0(uint256 genes) public onlyOwner returns (uint256) {
-      require(gen0Counter < maxGen0Hero, "Maximum number of Heros is reached. No new hero allowed!");
-      gen0Counter = SafeMath.add(gen0Counter, 1);
-      return _createHero(0, 0, 0, genes, msg.sender);
+  /**
+  * for player buy init heros
+   */
+  function buyInitHero(uint256 genes) public payable returns (uint256) {
+    require(gen0Counter < maxGen0Hero, "Maximum number of Heros is reached. No new hero allowed!");
+    require(msg.value >= initHeroPrice, "not enough money!");
+    gen0Counter = SafeMath.add(gen0Counter, 1);
+    return _createHero(0, 0, 0, genes, msg.sender);
+  }
+
+  function setInitHeroPrice(uint _price) external onlyOwner {
+    initHeroPrice = _price;
   }
 
   function _createHero(
@@ -67,19 +79,30 @@ contract CryptoHero is Ownable, IERC721 {
         uint256 _genes,
         address _owner
     ) internal returns (uint256) {
-        Hero memory _hero = Hero({
-            genes: _genes,
-            birthTime: uint64(block.timestamp),
-            mumId: uint32(_mumId),  //easier to input 256 and later convert to 32.
-            dadId: uint32(_dadId),
-            generation: uint16(_generation)
-        });
-        heros.push(_hero);
-        uint256 newHeroId = SafeMath.sub(heros.length, 1);//want to start with zero.
-        _transfer(address(0), _owner, newHeroId);//transfer from nowhere. Creation event.
-        emit Birth(_owner, newHeroId, _mumId, _dadId, _genes);
-        return newHeroId;
-    }
+      Hero memory _hero = Hero({
+          genes: _genes,
+          birthTime: uint64(block.timestamp),
+          mumId: uint32(_mumId),  //easier to input 256 and later convert to 32.
+          dadId: uint32(_dadId),
+          generation: uint16(_generation)
+      });
+      heros.push(_hero);
+      uint256 newHeroId = SafeMath.sub(heros.length, 1);//want to start with zero.
+      _transfer(address(0), _owner, newHeroId);//transfer from nowhere. Creation event.
+      emit HeroBirth(_owner, newHeroId, _mumId, _dadId, _genes);
+      return newHeroId;
+  }
+
+  function retireHero(uint256 heroId) internal {
+    delete heros[heroId];
+    emit HeroRetired(heroId);
+  }
+
+  function evolveHero(uint256 _heroId, uint256 _newGenes) internal {
+    uint256 _oldGenes = heros[_heroId].genes;
+    heros[_heroId].genes = _newGenes;
+    emit HeroEvolved(_heroId, _oldGenes, _newGenes);
+  }
   
   function getHero(uint256 tokenId) public view returns (
       uint256 genes,