why use blood for summoning contracts?

[xXFLAVORSXx]

if the summoning contracts need dna to be performed why does everybody use blood? as most people know dna is in every cell in our body so theoretically you could use saliva or feces because there is also dna in that and it would save the pain of having to bite yourself hard enough to bleed although im sure the ninja dont care about the pain since most are badass anyway

 

[The Demonic Kazekage]

i dont think anyone could bust a nut in the middle of a fight so....

 

[Gatsuuga]

Because stopping a fight so you can take a dump would be highly impractical.

 

[-Carnage-]

Dont overthink it dude.....

 

[LOVELESS]

Because blood is important

 

[Prime Rib]

beccause a blood contract for life.

 

[Dantee]

It's cooler

 

[Ōkami]

because they are better then written contracts?

 

[Straw Hat Zoro]

beccause a blood contract for life.

Because of this ^^^ a contract in blood is like a forever thing you bond to it by blood your very being.

 

[concept]

You have to sacrifice something to get something. What could be more practical in a fight than blood?

 

[Uxellius]

It's an idea you brought here but I believe it's symbolize the importance of the Summon-Summoner contract

 

[Straw Hat Zoro]

It's an idea you brought here but I believe it's symbolize the importance of the Summon-Summoner contract

It does it like the two of them are tied in each others life forever

 

[htmwall]

simple DNA

 

[Simple Math]

dna blood

 

[SuperFlyzzED]

Because the summon will recognize the user's blood. Once they know the user's blood that is the one summoning for their assistance. They will come and transport to the location of the user.

 

[Bad Touch Yakushi]

Looks cool. Plus have you ever seen Temari, Naruto or anyone ever flinch or get hurt from it? They're ninjas, it's no big deal to them :')