That depends on who or what you're talking about.
Jeff was a cannibal, he had eaten his brother.
Jeff's brother had been eaten.
I don't know why I felt the need to refer to cannibalism in order to provide this answer. I am not a cannibal, just in case you're wondering.
"Had been eating" is the past perfect progressive tense.
"Had been eating" is the past perfect continuous of eat.
The present perfect continuous tense of eat is:I/You/We/They have been eating.He/She/It has been eating.
The past tense of "exist" is "existed." The past perfect tense is "had existed."
The past perfect tense of hope is had hoped.
The past tense of "bleed" is "bled." The past perfect tense of "bleed" is "had bled."
The past tense of sit is sat. The past perfect tense of sit is had sat.
present tense past tense future tense present perfect tense past perfect tense future perfect tense present progressive tense past progressive tense future progressive tense present perfect progressive tense past perfect progressive tense future perfect progressive tense
The past perfect tense of 'get' is 'had gotten'
"Had been" is the past perfect tense of be.
The past perfect tense of "do" is "had done." For example, "She had done her homework before dinner."
Perfected is the past tense of perfect.
The past perfect tense of borrow is "had borrowed."