First of all La is a femenine pronoun and Mexico is a proper name but is not correct to use any pronouns it should be Viva Mexico without the La or El ( el is the masculine singular pronoun ).
Second of all well in the south i heard Guadalajara and Mexico City are known for their Metal activity but i hardly think you could find any death metal. Death metal is a weird animal here you could find enough black metal and power/heavy metal bands to fill up Lee B's wall with demos, but rarely does one run into death metal. Maybe in Mexico City but is too big and i do not know the city ( and i do not wish to ). Sadly my City ( Monterrey the biggest city in the North ) is the best example of Black and Heavy metal. On the black metal side we have darkness of blood ( they are as good as their cheesy name ) Life in mourning, Buzrael ( not shure if they still play )Morbeus, Argentum ( another band i really get bored with not to mention they have one of the most pretencious persons i know on guitar ) and probably another 10 or so black metal bands i did not bother to remember they names. On the Power metal side the city is even more crowded with untalented or unoriginal bands that i really put little to none atention, but one stands out a bit Horus ( but they changed their name already ) they are cool guys and really talented playing very classical heavy metal with an amazing Singer that gives a lot of deepth to the band and some nice guitar solos. About the only close to brutal bands are Dream of Nebiros wich are really laughable Doom metal with some of the worst musicians on the bass and guitars, and a vocalist that you will never notice unless he has a 1000 watts combo to back his amazing Brutal tone but amazingly low volume. Another Brutal band that often describes themselves as Grindcore metal are Arkarius, wich play amazing brutal death metal imho not so much grindcore influenced but enough to be part of their style in a noticeable fashion, again a really talented guitar player that lies down some of the most amazing swepts ive seen but unfortunately their guitarplayer is gone to DF cause he is getting married so they will be unactive until next year.
The melodic side is even more little, There are some friends Nightshades that play some really nice melodic death metal in the vein of DT's skydancer with black metal influences (their guitar player used to play in a band caller Belzabeth or something like that not really my kind of thing: Black metal. ) Their lyrics are also interesting circulating around the Aztec Culture really something to see. Then we have Father of Lies wich are also melodic death metal but i never met but their style is quite nice too. There is Us Koldun Playing Melodic Death metal with jazz interludes and improvisations, and there is a friend that is putting togheter a melodic metal band in the vein of new inflames but he has not played live anywhere yet. Sadly there is not much going on but by the end of the year chances are we are gonna play with Argentum and other black metal bands and other curiosities, the gig is not confirmed but it shurely could happen if you at are thinking of spending some time in the North and decide to visit Monterrey say so and ill show you around some local acts ( lets just hope your timming is right and there is something to see cause there seem to be weeks when nothing happens ).