This monster can easily be Fusion Summoned this card with "Dragon's Mirror".
"Necroface" can be used to mill the opponent's Deck and/or banish some of your Zombies for an effect that uses them from the Banished Zone (such as good "Shutendoji").
This card is completely useless when battling against an opponent's defense position monster or while you have no tokens whose ATK is higher than that monster's DEF; to remedy that: use cards like "Shield Crush" or "Fairy Meteor Crush".
This card work well in a "Reptilianne" deck. As this card's effect includes reducing the ATK of the opponent's monster to 0, it can help the Reptilianne cards to activate their effects, however, the Reptilianne aren't "Zombie-TypeMonsters , therefore you will need either "Zombie World" or "Dna Surgery" with "Polymerization" or "Super Polymerization" to make possible the summoning of this card
Any Deck featuring Zombie-Type monsters can easily use this card as an "ace-in-the-hole". With only two Zombie-Type monsters and a Fusion Summoning card needed, it is usually only a "Polymerization" needed to bring this into a "Zombie World" or "Wight" Deck.
A good card to have out is "Kishido Spirit". This way if your opponent has a monster with the same attack points as Dragonecro, you can get a powerful token out of the attack.
Since most Zombie monsters have effects that benefit or activate when sent to the graveyard, this card can be used as a quick way to get two zombies in your hand into the graveyard quickly to get their effects off.