Not sure if this is all the riffs but its all the main ones
and any others would be easy to figure out
Lead riff
E:|---------------|
B:|---------------|
G:|---------------|
D:|5-----5---5-7^-|
A:|--7-----7------|
D:|---------------|
[ Tab from: https://www.guitartabs.cc/tabs/m/my_ruin/rockstar_tab.html ]
Intro Riff and break riff
E:|---------------|
B:|---------------|
G:|---------------|
D:|52-5257-52-5257|
A:|52-5257-52-5257|
D:|52-5257-52-5257|
Verse riff
E:|---------------------------|
B:|---------------------------|
G:|---------------------------|
D:|22-030-22-030-22-030-22-030|
A:|22-030-22-030-22-030-22-030|
D:|22-030-22-030-22-030-22-030|
Chorus riff
E:|---------------|
B:|---------------|
G:|---------------|
D:|02222-0-203----|
A:|02222-0-203----|
D:|02222-0-203----|
