Thanks Miland.

Bennon:Using the conditional would have obfuscated the "it already happened" sentiment. If the conditional would have been used, it would imply that the hero might not come, but we use an indicative(ish) because we know he already did.
[...]
If the protasis did use the conditional -US, how would the speaker indicate that it already happened and we know the hero did come?

In Esperanto the conditional ending -us is time neutral and thus can be used to show a conditional mood that exists at any time, past present or future, so it's fine for the protasis. I know some people view this as a quite intolerable ambiguity but I've never really found it a problem. Bear in mind that much of the time it's not even necessary to explicitly indicate that the conditionality existed in the past (as we tend to do as a matter of course in our own language English) because context will already make it obvious. When it is not clear there are various ways you can indicate the pastness, such as use of the -int participle as darkweasel already demonstrated, or time-sense words like "tiam", "antaŭe", "jam" etc. You can make your own judgement about which is the most accurate/elegant or whatever. Personally I have found that the suitability of each of these methods depends on the unique and particular context of the situation you're trying to explain, making across-the-board recommendations like "just use a simple -us verb plus a time word" or "avoid the participles because they are pointless" quite inappropriate. They all have their uses in certain cases.

Most of the time simple phrases like "se li ne venus la homo mortus" will be very easily understood to be related to the past, if that was the intended sense, without any need for clarificatory devices. It could be that in the preceeding text some reference was made to the fact he actually came, so we already know we're talking about an actual thing that happened in the past. It could just be that the whole story is about past events and so we infer the pastness naturally from the context. What I have experienced in the language suggests to me these simple forms are more usual and to be preferred wherever possible. In those instances where some time-sense confusion arises then there are tools at your disposal to remove it, but to my understanding resorting to the past tense is neither a desirable or correct means of doing so.

erinja:...They are not used frequently, and if you over-use them, thereby making your tenses more specific than strictly necessary, people can get the wrong idea. Also, your speaking becomes overly wordy and not very elegant.

It isn't wrong. But people could potentially misunderstand you in the sense that they think you're trying to emphasize the exact timing of things, when you're not ...

Ok. Thanks Erinja for your explanation. Ii's useful for me.

Ĝis, Novatago

Miland:
In the case of a certain future event you could add a time qualification after using onto e.g. La kondamnito estis punota dum la sekva monato.

I think this sentence means:
"La kondamnito estis punota dum la sekva monato, do li estis punata dum la post-sekva monato". If he "estis punota" during that month, the punishment occurred only after that period.

marcuscf:La kondamnito estis punota dum la sekva monato.
I think this sentence means:
"La kondamnito estis punota dum la sekva monato, do li estis punata dum la post-sekva monato". If he "estis punota" during that month, the punishment occurred only after that period.

Yes, although he was on the verge of being punished during that time, so that it could have happened at any time during that period.