is this giratina worth keeping for competitive

[THE ARBITER]

it is calm and the iv spread is hp 19 atk 24 def 27 spa 28 sp def 12 spd 27
is this iv spread worth keeping i want to use it competitively
also if it is deemed not i can reset (it's the shiny giratina  from the 2013 event )

[SaRo|Rapidash]

Generally speaking, Giratina likes being Impish this gen, and none of those stats are perfect.

If you have enough time, I'd try and get an Impish one with 31 Speed and decent defences (20+). 31 Speed is almost a necessity in competitive, although you could make do with 29-30 and just make sure you put 4-8 EVs in to make it up, as you really shouldn't be any slower than maximum.

However, if you don't have enough time to reset for that, the one you have isn't bad. Calm, whilst not ideal, is not a bad nature for Giratina, but the problem is really the speed, Giratina is at 90 Base Speed, which in Übers is a fairly common speed with things like Dialga, Ho-oh, Kyogre and Groudon speed tying. Groudon is especially relevant, as you'll like to be able to WoW it before it can do any damage to you.

Tl;dr - you could do with soft-resetting for Impish w/ 31 Speed, but if that's too much effort the one you have isn't bad.

[THE ARBITER]

im going to give it some more shots and besides i can do this anytime i want i wish i could rng though

[SaRo|Rapidash]

If you're interested in learning RNG, I suggest taking a look at this, but it's a bit long-winded and takes ages to get your first one right. Also really difficult on a 3DS, not impossible but difficult.

[THE ARBITER]

i gave up at step 5

[THE ARBITER]

how about this naive one 29 hp 26 atk 21 def 25 sp atk 29 sp def 24 speed

[Raphetty]

how about this naive one 29 hp 26 atk 21 def 25 sp atk 29 sp def 24 speed

Stick with Impish or Careful, depending if you want more Defense or Sp. Def, and that's if you're using a physical attack like Dragon Tail. With no attacks or with a special attack you can use Bold or Calm.