Remove Duplicates after merging tables

I have what is probably a really dumb issue, but I am a powerquery/DAX noob. 🙂

I am taking several datasets with data that looks like this: 

and appending them together to create a 'master list' of machine name.

When I append the data tables together and 'remove duplicates' on column #1, i can't get it to remove duplicates, because they'll be formatted like this:

I don't care which one it keeps, but I am assuming as long as theres another column with different data it will never see that 2nd row as a duplicate.

If I start with each table, and try to merge the queries, It wont let me consolidate the columns either.

E.g. it will do this:

Do I have to merge the sources and then somehow concatenate the columns down to 1? I don't know how to scrub that as it's going to be a mix of nulls and some where it gets results for each table.

Thanks in advance!!