Use "DNA Surgery" when you summon "The Hunter with 7 Weapons" and choose 1 Type of monster. Its ATK will increase every time it attacks or is attacked.
This card works well with "Zombie World" and "The Lady in Wight". Select "Zombie" for this card's effect: it will gain attack against every monster, and it will be protected by "The Lady in Wight", as it's a level 3 monster and now a Zombie (see this ruling article).
Since this monster has 1000 as Orignal ATK, "Unstable Evolution" has no drawback in case your life points are higher. In case they are lower, it will have 2400 Original ATK.