Hi! See first command for da FIRE SWORD:
/give @p iron_sword 1 0 {display:{Name:"Fire Sword"},ench:[{id:20,lvl:10,Unbreakable:1}]}
Number two is in da box. Number 3-11:
/scoreboard objectives add damage stat.damageDealt
/gamerule commandBlockOutput false
/scoreboard players set @a FireSword 0
/scoreboard players set @a FireSword 1 {SelectedItemSlot:0,Inventory:[{Slot:0b,tag:{display:{Name:"Fire Sword"}}}]}
/testfor @a[score_damage_min=1]
/execute @p[score_damage_min=1] ~ ~ ~ particle flame ~ ~1 ~ 1 3 1 0.03 100 @e[type=!Player,r=6]
/effect @a[score_FireSword,min=1] minecraft:fire_resistance 1 0 true
/execute @p[score_damage_min=1] ~ ~ ~ execute @e[r=6,type=!Player] ~ ~ ~ setblock ~1 ~ ~ minecraft:fire
/execute @p[score_damage_min=1] ~ ~ ~ execute @e[r=6,type=!Player] ~ ~ ~ setblock ~-1 ~ ~ minecraft:fire
/execute @p[score_damage_min=1] ~ ~ ~ execute @e[r=6,type=!Player] ~ ~ ~ setblock ~ ~ ~1 minecraft:fire
/execute @p[score_damage_min=1] ~ ~ ~ execute @e[r=6,type=!Player] ~ ~ ~ setblock ~ ~ ~-1 minecraft:fire
/scoreboard players set @p[score_damage_min=1] damage 0
See
Fire Blade: How To Make Elemental Swords In Minecraft, NO MODS!!! - YouTube